{
  "spore": "profile",
  "id": "crystal-quartz",
  "spore_version": "0.2",
  "family": "optical-crystals",
  "name": "Crystal quartz (alpha-quartz single crystal, SiO2)",
  "abbreviation": "SiO2",
  "role": "birefringent optical retarder, polariser and piezoelectric frequency-control crystal",
  "category": "glasses-optics",
  "type": "optical-crystals",
  "summary": "Crystal quartz is alpha-quartz, crystalline silicon dioxide grown as a single crystal for optics and frequency control. Crystran gives a density of 2.649 g/cc and a melting point of 1710 °C, and says quartz should not be used above 490 °C because it starts to revert to a glassy state. Korth Kristalle gives a maximum application temperature above 1200 °C, so the two suppliers disagree on the usable limit.\n",
  "best_for": "Birefringent optics such as wave plates and polarisers, and piezoelectric frequency control in electronics.",
  "weakest_at": "Heat: Crystran says it starts to revert to a glassy state above 490 °C, far below its 1710 °C melting point.",
  "identity": {
    "formula": "SiO2",
    "cas": "14808-60-7",
    "crystal_system": "trigonal (hexagonal axes); Korth Kristalle gives a = 4.9138 Å and c = 5.4052 Å",
    "space_group": "P3(2)21 (RH) and P3(1)21 (LH)",
    "designations": [],
    "source": "crystran-quartz-page",
    "where": "Product Data table, Class/Structure row (Trigonal (hex) P3(2)21 (RH) and P3(1)21 (LH)); formula from the page heading Crystal Quartz SiO2; CAS 14808-60-7 from crystran-quartz-sds section 3.1; lattice constants from korth-quartz, Crystal Structure row"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "total-radiation-dose"
    ],
    "applications": [
      "optics-and-cameras",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, Crystran",
      "value": 2.649,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "synthetic optical-grade crystal (alpha-quartz)",
        "temperature": "not stated on the page",
        "unit_in_source": "g/cc"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Density row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, Korth Kristalle",
      "value": 2.65,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "synthetic single crystal (hydrothermal)",
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "source": "korth-quartz",
      "where": "Properties table, Density row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, Crystran",
      "value": 1710,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "synthetic crystal"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "note": "Korth Kristalle gives 1723 °C for the same material; the two values differ and both are kept.",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Melting Point row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, Korth Kristalle",
      "value": 1723,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "synthetic single crystal"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "note": "Crystran gives 1710 °C for the same material; the two values differ and both are kept.",
      "source": "korth-quartz",
      "where": "Properties table, Melting point row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "boiling_point",
      "label": "Boiling point at 760 mm Hg, as printed in the safety data sheet",
      "value": 2230,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "760 mm Hg, as printed"
      },
      "method": "Value printed in a supplier safety data sheet",
      "status": "ground",
      "note": "Printed only in the safety data sheet; the Crystran data sheet and the Korth Kristalle page give no boiling point.",
      "source": "crystran-quartz-sds",
      "where": "Section 9.1, Boiling point (760mm Hg) row",
      "source_detail": {
        "title": "Safety Data Sheet: Quartz (SiO2) Optical Crystal, Crystran Ltd",
        "id": "revision 2016, issued 12 October 2016",
        "url": "https://www.crystran.com/wp-content/uploads/2025/09/quartz-crystal-sio2-msds.pdf",
        "year": 2016,
        "kind": "datasheet",
        "license": "supplier document, cited not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, para direction (as printed by Crystran)",
      "value": 10.7,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "323 K",
        "orientation": "para, as printed (the page does not define the direction)",
        "unit_in_source": "W m-1 K-1"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Thermal Conductivity row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, perp direction (as printed by Crystran)",
      "value": 6.2,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "323 K",
        "orientation": "perp, as printed (the page does not define the direction)",
        "unit_in_source": "W m-1 K-1"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Thermal Conductivity row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, parallel to the c axis (Korth Kristalle)",
      "value": 11.7,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "293 K",
        "orientation": "parallel to the c axis, as printed as || C"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "source": "korth-quartz",
      "where": "Properties table, Thermal Conductivity row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity, Crystran",
      "value": 710,
      "bound": "exact",
      "unit": "J/(kg·K)",
      "scope": "material",
      "conditions": {
        "temperature": "not stated on the page",
        "unit_in_source": "J Kg-1 K-1"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Specific Heat Capacity row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity, Korth Kristalle",
      "value": 744,
      "bound": "exact",
      "unit": "J/(kg·K)",
      "scope": "material",
      "conditions": {
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "note": "Crystran gives 710 J/(kg·K); the two values differ and both are kept.",
      "source": "korth-quartz",
      "where": "Properties table, Spec. Heat Capacity row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, para direction (as printed by Crystran)",
      "value": 97.2,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "orientation": "para, as printed (the page does not define the direction)",
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Youngs Modulus (E) row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, perp direction (as printed by Crystran)",
      "value": 76.5,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "orientation": "perp, as printed (the page does not define the direction)",
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Youngs Modulus (E) row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, parallel to the c axis (Korth Kristalle)",
      "value": 97,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "orientation": "parallel to the c axis, as printed as || C",
        "temperature": "25 °C"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "note": "Crystran gives 97.2 GPa in the para direction; the two values agree closely but are kept with their sources.",
      "source": "korth-quartz",
      "where": "Properties table, Young's Modulus row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Shear modulus, Crystran",
      "value": 31.14,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Shear Modulus (G) row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "label": "Bulk modulus, Crystran",
      "value": 36.4,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "note": "Korth Kristalle gives 98 GPa for bulk modulus; the sources disagree and both are kept.",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Bulk Modulus (K) row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "label": "Bulk modulus, Korth Kristalle",
      "value": 98,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "note": "Crystran gives 36.4 GPa for bulk modulus; the sources disagree and both are kept.",
      "source": "korth-quartz",
      "where": "Properties table, Bulk Modulus row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson's ratio, Korth Kristalle",
      "value": 0.08,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "temperature": "not stated on the page"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "note": "Crystran prints n/a for Poisson ratio.",
      "source": "korth-quartz",
      "where": "Properties table, Poisson Ratio row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant, para direction (as printed by Crystran)",
      "value": 4.34,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "30 MHz",
        "orientation": "para, as printed (the page does not define the direction)"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "note": "Korth Kristalle assigns 4.27 to the parallel direction and 4.34 to the perpendicular one, the reverse of this row.",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Dielectric Constant row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant, perp direction (as printed by Crystran)",
      "value": 4.27,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "30 MHz",
        "orientation": "perp, as printed (the page does not define the direction)"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Dielectric Constant row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Ordinary refractive index, no (Crystran)",
      "value": 1.54421,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "0.6 µm",
        "ray": "ordinary (no), as printed"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Refractive Index row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Extraordinary refractive index, ne (Crystran)",
      "value": 1.55333,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "0.6 µm",
        "ray": "extraordinary (Ne), as printed"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Refractive Index row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Ordinary refractive index, no (Korth Kristalle)",
      "value": 1.543,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "633 nm",
        "ray": "ordinary (no), as printed"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "source": "korth-quartz",
      "where": "Properties table, Refractive Index row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Extraordinary refractive index, ne (Korth Kristalle)",
      "value": 1.552,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "633 nm",
        "ray": "extraordinary (ne), as printed"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "source": "korth-quartz",
      "where": "Properties table, Refractive Index row",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "transmission_range",
      "label": "Transmission range, Crystran",
      "value": 0.18,
      "value_high": 3.5,
      "bound": "range",
      "unit": "µm",
      "scope": "material",
      "conditions": {
        "thickness": "not stated on the page",
        "note": "a second band of 40 to 100 µm is printed separately"
      },
      "method": "Range printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Transmission Range row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "transmission_range",
      "label": "Transmission range, Korth Kristalle",
      "value": 0.15,
      "value_high": 4.1,
      "bound": "range",
      "unit": "µm",
      "scope": "material",
      "conditions": {
        "thickness": "2 mm"
      },
      "method": "Range printed on a manufacturer material page (English version)",
      "status": "ground",
      "source": "korth-quartz",
      "where": "Properties table, Transmission Range row (thickness 2 mm)",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Upper temperature limit for use, Crystran",
      "value": 490,
      "bound": "upper",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "stated as: should not be processed or used at temperatures greater than 490 °C"
      },
      "method": "Limit printed as a warning in the product description on a manufacturer page",
      "status": "ground",
      "note": "Korth Kristalle gives a maximum application temperature above 1200 °C; the two limits conflict and both are kept.",
      "source": "crystran-quartz-page",
      "where": "Product description paragraph (Quartz should not be processed or used at temperatures greater than 490 °C)",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum application temperature, Korth Kristalle",
      "value": 1200,
      "bound": "lower",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "printed as: max. temperature for application > 1200°C"
      },
      "method": "Value printed on a manufacturer material page (English version)",
      "status": "ground",
      "note": "Crystran gives an upper limit of 490 °C for use; the two limits conflict and both are kept.",
      "source": "korth-quartz",
      "where": "Remarks, Quartz is common, max. temperature for application > 1200°C",
      "source_detail": {
        "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
        "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "knoop_hardness",
      "label": "Knoop hardness, Crystran",
      "value": 741,
      "bound": "exact",
      "unit": "HK",
      "scope": "material",
      "conditions": {
        "load": "500 g indenter",
        "unit_in_source": "printed as Knoop 741 with 500g indenter; no separate unit printed"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Hardness row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_limit",
      "label": "Apparent elastic limit, Crystran",
      "value": 41,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "test": "not stated on the page",
        "unit_in_source": "MPa (5950psi printed)"
      },
      "method": "Value printed on a manufacturer product data page",
      "status": "ground",
      "source": "crystran-quartz-page",
      "where": "Product Data table, Apparent Elastic Limit row",
      "source_detail": {
        "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
        "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
        "kind": "datasheet",
        "license": "supplier web page, cited not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Hydrofluoric acid, fluosilicic acid, phosphoric acid and strong hot alkali solutions",
      "headline": "Hydrofluoric acid and hot concentrated alkalis damage quartz, but no data sheet gives a rate.",
      "effect": "Korth Kristalle states that quartz will be damaged by contact with HF and hot concentrated alkalines. Crystran's safety data sheet lists strong hot alkali solutions and hydrofluoric, fluosilicic and phosphoric acids as conditions to avoid. Neither source gives a rate or a time, so the rating is unknown.",
      "rating": "unknown",
      "conditions": {
        "basis": "statements in two supplier documents; no test or exposure time given"
      },
      "source": "korth-quartz",
      "where": "Remarks; Crystran SDS is cited in the same entry's effect text (crystran-quartz-sds, section 10.4)"
    },
    {
      "environment": "Strong mineral acids",
      "headline": "Crystran lists strong mineral acids as incompatible; Korth Kristalle says quartz is insoluble in acids.",
      "effect": "Crystran's safety data sheet says quartz reacts with some mineral acids and lists strong mineral acids as incompatible. Korth Kristalle describes quartz as unsoluble in acids. The two statements differ, and no rate is given.",
      "rating": "unknown",
      "conditions": {
        "basis": "supplier safety data sheet statements; no test given"
      },
      "source": "crystran-quartz-sds",
      "where": "Sections 10.1 and 10.5"
    },
    {
      "environment": "Water",
      "headline": "Solubility in water is described differently by the two Crystran documents.",
      "effect": "Crystran's data sheet lists solubility as Insoluble in water. Crystran's safety data sheet describes the product as practically soluble in water. The NTP profile of crystalline silica describes silica as practically insoluble in water at 20°C. No dissolution rate is given in any source.",
      "rating": "unknown",
      "conditions": {
        "basis": "statements in supplier and government documents; no test given"
      },
      "source": "crystran-quartz-sds",
      "where": "Section 9.1, Solubility in water row"
    },
    {
      "environment": "Heating above the reversion limit (thermal ageing)",
      "headline": "Above 490 °C quartz reverts to a glassy state, and Crystran says fracture is probable.",
      "effect": "Crystran says crystal quartz starts to revert to a glassy state above 490 °C and that the process is complete by 530°C. It adds that, as annealing is unlikely, fracture of the component is probable. The rating is severe because the page states that fracture is probable.",
      "rating": "severe",
      "conditions": {
        "temperature_range": "above 490 °C, complete by 530°C"
      },
      "source": "crystran-quartz-page",
      "where": "Product description paragraph"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Crystran's safety data sheet says the product is 'No Hazardous Product as specified in Directive 67/548/EEC' and gives the precautionary statement P262, Do not breathe dust/fume/gas/mist/vapours/spray.",
        "ghs": [],
        "source": "crystran-quartz-sds",
        "where": "Sections 2.1 and 2.2"
      },
      {
        "text": "Crystran's safety data sheet gives an occupational limit of 'Total inhalable silica dust: Long term 0.1 mg/m3'.",
        "ghs": [],
        "source": "crystran-quartz-sds",
        "where": "Section 8.1, Control parameters"
      },
      {
        "text": "Respirable crystalline silica, primarily quartz dust, is 'Known to be a human carcinogen' in the NTP Report on Carcinogens.",
        "ghs": [],
        "source": "ntp-silica",
        "where": "Silica, Crystalline (Respirable Size) profile, Known to be a human carcinogen line"
      },
      {
        "text": "PubChem's GHS summary for the generic Silica record (CID 24261), which is not specific to quartz, includes a block with 'H350 (12.6%): May cause cancer', 'H372 (46%)' and 'H373 (29.4%)' from aggregated company reports.",
        "ghs": [
          "H350",
          "H372",
          "H373"
        ],
        "source": "pubchem-silica",
        "where": "Safety and Hazards, GHS Classification (Danger block)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Reversion to a glassy state on heating",
        "trigger": "Use or processing above 490 °C",
        "consequence": "Crystran says crystal quartz starts to revert to a glassy state above 490 °C, the process is complete by 530°C, and fracture of the component is probable.",
        "severity": "high",
        "source": "crystran-quartz-page",
        "where": "Product description paragraph"
      },
      {
        "mode": "Cracking at the alpha-to-beta transition",
        "trigger": "Heating through the change to beta (high) quartz; the temperature is not given by Korth Kristalle",
        "consequence": "Korth Kristalle says the change to beta quartz is reversible but can lead to breaks or cracks in the material.",
        "severity": "moderate",
        "source": "korth-quartz",
        "where": "Remarks, standard modification text"
      },
      {
        "mode": "Frequency shift of quartz resonators in space radiation",
        "trigger": "Exposure on NASA's Long Duration Exposure Facility (LDEF)",
        "consequence": "Resonators of swept premium-Q quartz showed a frequency change attributed to recovery of radiation damage; resonators of natural quartz did not.",
        "severity": "moderate",
        "source": "nasa-ntrs-19920018076",
        "where": "Abstract"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Protect the material against physical damage and avoid generating dust (Crystran SDS, section 7.2).",
        "source": "crystran-quartz-sds",
        "where": "Section 7.2"
      },
      {
        "text": "Safety goggles or safety glasses with side shields are required if there is any possibility of chipping or dust creation; wash hands after handling.",
        "source": "crystran-quartz-sds",
        "where": "Section 8.1, Exposure controls"
      },
      {
        "text": "Keep away from strong mineral acids and hydrofluoric acid; the SDS lists them as incompatible or conditions to avoid.",
        "source": "crystran-quartz-sds",
        "where": "Sections 10.4 and 10.5"
      }
    ],
    "mitigations": [
      {
        "text": "Keep use and processing below 490 °C, as Crystran advises.",
        "source": "crystran-quartz-page",
        "where": "Product description paragraph"
      }
    ]
  },
  "uses": [
    {
      "application": "optics-and-cameras",
      "device": "Quarter-wave plates and polarisers (wave retardation)",
      "example": "Crystran says crystalline quartz is used extensively as a wave retardation medium in quarter-wave plates and in polarisers. Korth Kristalle lists the same main applications: polariser, wave or retardation plate and VUV filter.",
      "source": "crystran-quartz-page",
      "where": "Product description paragraph; Korth Kristalle Remarks"
    },
    {
      "application": "electronics-and-chips",
      "device": "Frequency-control oscillators, frequency filters and timers",
      "example": "The USGS 2026 chapter says electronic-grade quartz crystal is used to make frequency controls, frequency filters and timers in electronic circuits, and that electronic applications account for most industrial uses of quartz crystal.",
      "source": "usgs-mcs2026-quartz",
      "where": "Industrial cultured quartz crystal section, first paragraph"
    },
    {
      "application": "electronics-and-chips",
      "device": "Quartz crystal resonators exposed on NASA's Long Duration Exposure Facility",
      "example": "A 1992 LDEF symposium abstract reports that resonators of swept premium-Q quartz changed frequency after space exposure, while resonators of natural quartz did not.",
      "source": "nasa-ntrs-19920018076",
      "where": "Abstract"
    }
  ],
  "supply": [
    {
      "subject": "Cultured piezoelectric quartz crystal, United States imports by origin (2021 to 2024)",
      "producers": [
        {
          "country": "China",
          "share_percent": 89,
          "year": 2024
        },
        {
          "country": "Denmark",
          "share_percent": 3,
          "year": 2024
        },
        {
          "country": "Japan",
          "share_percent": 3,
          "year": 2024
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: an unspecified amount of rejected cultured quartz crystal was used as feed material for the production of cultured quartz crystal.",
      "substitutes": [
        "USGS: silicon is increasingly being used as a substitute for quartz crystal for frequency-control oscillators in electronic circuits.",
        "USGS: cultured quartz can be used as a substitute for ground high-purity quartz, although it is not commonly done owing to the high price of cultured quartz."
      ],
      "source": "usgs-mcs2026-quartz",
      "where": "Import Sources (2021-24) line; Recycling; Substitutes. The share of 'other' (5%) is not a country and is omitted."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Crystal Quartz (SiO2) safety data sheet, Crystran Ltd (revision 2016)",
      "type": "sds",
      "url": "https://www.crystran.com/wp-content/uploads/2025/09/quartz-crystal-sio2-msds.pdf",
      "year": 2016
    },
    {
      "title": "Quartz Crystal (SiO2) data sheet, Crystran Ltd",
      "type": "datasheet",
      "url": "https://www.crystran.com/wp-content/uploads/2025/09/quartz-crystal-sio2-data-sheet.pdf",
      "year": 2025
    },
    {
      "title": "SiO2 Quartz Crystal material page, Korth Kristalle GmbH",
      "type": "datasheet",
      "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal"
    },
    {
      "title": "Mineral Commodity Summaries 2026: Quartz (high-purity and industrial cultured crystal), USGS",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-quartz.pdf",
      "year": 2026
    },
    {
      "title": "Study of factors determining the radiation sensitivity of quartz crystal oscillators (NASA NTRS 19920018076)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19920018076",
      "year": 1992
    },
    {
      "title": "PubChem: Silica (CID 24261), GHS classification summary",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/24261"
    },
    {
      "title": "NTP Report on Carcinogens, Fifteenth Edition: Silica, Crystalline (Respirable Size)",
      "type": "report",
      "url": "https://ntp.niehs.nih.gov/ntp/roc/content/profiles/silica.pdf"
    }
  ],
  "gaps": [
    "Thermal expansion coefficients (parallel and perpendicular directions) are printed with powers of ten on both the Crystran and Korth Kristalle pages, so they are left out.",
    "The Korth Kristalle hardness row is labelled Mohs but gives a Knoop-scale figure; it is not recorded. The Mohs hardness value was not taken from a data sheet in this run.",
    "The Korth Kristalle perpendicular thermal conductivity is printed without a unit, so it is left out.",
    "The alpha-to-beta transition temperature is not taken from a data source in this run; Wikipedia is used here only for composition and history.",
    "No space-environment numbers were found beyond the LDEF abstract, which gives no values; no flight data, orbit or dose figures were recorded.",
    "Crustal abundance of quartz was not found in the USGS chapter, which gives no mine production shares for the world.",
    "The USGS chapter does not state critical-mineral status for quartz crystal, so no critical-list entries are recorded.",
    "Atomic weights for the recipe were not taken: the NIST table page fetched was the all-elements table, without a usable single-element row.",
    "Non-canonical property names used: knoop_hardness, elastic_limit and transmission_range. They are not in spores/property-canon.yaml.",
    "Dielectric, bulk modulus and maximum temperature values differ between Crystran and Korth Kristalle; both are kept with their sources and no value was chosen.",
    "No ultraviolet or radiation transmission data were found for this grade; the LDEF abstract is qualitative only."
  ],
  "story": {
    "why": "Crystal quartz is single-crystal silicon dioxide grown for optics and frequency control. Crystran says optical quartz is used extensively as a wave retardation medium; the crystal has two refractive indices (1.54421 and 1.55333 at 0.6 µm). It is piezoelectric, and electronic-grade quartz crystal is used for frequency controls. Its limit is heat: the crystal reverts to a glassy state above 490 °C.",
    "uses": [
      {
        "where": "Wave plates and polarisers",
        "line": "Crystran says crystalline quartz is used extensively as a wave retardation medium in quarter-wave plates and in polarisers. Korth Kristalle names the same main optical applications."
      },
      {
        "where": "Frequency control in electronics",
        "line": "The USGS 2026 chapter says electronic-grade quartz crystal is used for frequency controls, frequency filters and timers, and that electronics accounts for most industrial uses of quartz crystal."
      },
      {
        "where": "Tested as resonators in space",
        "line": "A 1992 NASA abstract reports that quartz resonators of swept premium-Q material changed frequency after exposure on the Long Duration Exposure Facility, while resonators of natural quartz did not."
      }
    ],
    "can_do": [
      {
        "label": "Optical transmission",
        "line": "It transmits from the ultraviolet into the near infrared. Crystran and Korth Kristalle print different ranges, and both are kept.",
        "benchmark": "transmission_range",
        "scope": "material",
        "value": "0.18 to 3.5 µm (Crystran); 0.15 to 4.1 µm (Korth, 2 mm)"
      },
      {
        "label": "Birefringence",
        "line": "The two refractive indices differ, so light polarised along different axes travels at different speeds. This is the property that makes wave plates work.",
        "benchmark": "refractive_index",
        "scope": "material",
        "value": "1.54421 and 1.55333 at 0.6 µm (Crystran)"
      },
      {
        "label": "Stiffness",
        "line": "Young's modulus is 97.2 GPa in the para direction and 76.5 GPa in the perp direction, as Crystran prints them. The page does not define the directions.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "97.2 GPa and 76.5 GPa (Crystran, para and perp)"
      },
      {
        "label": "Hardness",
        "line": "Crystran gives a Knoop hardness of 741 with a 500 g indenter.",
        "benchmark": "knoop_hardness",
        "scope": "material",
        "value": "Knoop 741 with a 500 g indenter (Crystran)"
      },
      {
        "label": "Heat limit",
        "line": "Crystran says quartz should not be used above 490 °C. Korth Kristalle gives a maximum application temperature above 1200 °C. The two limits conflict, and the lower one is the safer guide.",
        "benchmark": "max_service_temp",
        "scope": "material",
        "value": "490 °C (Crystran) and above 1200 °C (Korth)"
      }
    ],
    "compare": "Crystran notes that fused quartz is the glassy, non-crystalline form better known as silica, so the two should not be confused. Crystal quartz is birefringent, and that property is why it is used for wave plates. Its melting point is 1710 °C (Crystran), but Crystran's use limit is 490 °C because above that temperature the crystal reverts to a glassy state. The table compares its density, melting point and thermal conductivity.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      }
    ],
    "handling": [
      "Avoid generating dust. Crystran's safety data sheet says to protect the material from physical damage and avoid generating dust.",
      "Wear safety glasses with side shields where chipping or dust is possible.",
      "Keep it away from strong mineral acids and hydrofluoric acid, which the data sheets list as incompatible or damaging.",
      "Keep use and processing below 490 °C, as Crystran advises."
    ],
    "good_for": [
      "Wave plates and polarisers. Crystran and Korth Kristalle both name these as the main optical uses.",
      "Frequency control. The USGS names frequency controls, filters and timers as the main electronic use of cultured quartz.",
      "Windows and optics from the ultraviolet to the near infrared, within the temperature limit above."
    ],
    "watch_out": [
      "Heat. Crystran says quartz reverts to a glassy state above 490 °C, far below its 1710 °C melting point.",
      "Acids and hot alkalis. Korth Kristalle says hydrofluoric acid and hot concentrated alkalis damage it.",
      "Conflicting data sheets. Density, specific heat, bulk modulus, dielectric direction and maximum temperature differ between Crystran and Korth Kristalle.",
      "Cracking on phase change. Korth Kristalle says the alpha-to-beta change can lead to breaks or cracks.",
      "Radiation. A NASA abstract reports frequency shifts in swept premium-Q resonators after LDEF exposure."
    ],
    "verdict": "Quartz is a well-documented birefringent optical and frequency-control crystal. Its data sheets disagree on several values and on the usable heat limit, so check the supplier's current datasheet before design use.",
    "recipe": {
      "line": "Quartz is crystalline silicon dioxide, SiO2. Each silicon atom sits at the centre of a tetrahedron of four oxygen atoms, and the tetrahedra share corners to form a framework (Wikipedia). Optical quartz is grown synthetically by a hydrothermal process at high temperature and pressure (Korth Kristalle).",
      "parts": [
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Centre of each SiO4 tetrahedron, the building block of the framework that gives quartz its crystal structure.",
          "source": "wikipedia-quartz",
          "where": "Composition and crystal structure text"
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Shared between two tetrahedra in the framework; with one silicon it gives the SiO2 formula.",
          "source": "wikipedia-quartz",
          "where": "Composition and crystal structure text"
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The supplier says the product is not hazardous as a substance, but the dust is a recognised carcinogen risk.",
        "points": [
          {
            "label": "The product",
            "line": "Crystran's safety data sheet says it is not a hazardous product under Directive 67/548/EEC and gives the precautionary statement P262: do not breathe dust."
          },
          {
            "label": "Respirable dust",
            "line": "The NTP lists respirable crystalline silica, mainly quartz dust, as known to be a human carcinogen."
          },
          {
            "label": "Limit",
            "line": "Crystran's safety data sheet gives a long-term limit of 0.1 mg/m3 for total inhalable silica dust."
          }
        ],
        "level": 2,
        "verdict": "Dust is the hazard; avoid breathing it"
      },
      {
        "title": "If it overheats",
        "lead": "Heating changes the crystal structure, so the limit is set by the structure, not by the melting point.",
        "points": [
          {
            "label": "Above 490 °C",
            "line": "Crystran says the crystal starts to revert to a glassy state above 490 °C, the change is complete by 530°C, and fracture of the component is probable."
          },
          {
            "label": "Cracking",
            "line": "Korth Kristalle says the alpha-to-beta change is reversible but can lead to breaks or cracks."
          }
        ],
        "level": 2,
        "verdict": "Fracture risk above 490 °C"
      },
      {
        "title": "Chemicals",
        "lead": "The data sheets name specific chemicals to avoid.",
        "points": [
          {
            "label": "Acids and alkalis",
            "line": "Korth Kristalle says hydrofluoric acid and hot concentrated alkalis damage quartz. Crystran lists strong hot alkali solutions and hydrofluoric, fluosilicic and phosphoric acids as conditions to avoid."
          }
        ],
        "level": 1,
        "verdict": "Keep away from strong acids and hot alkali"
      }
    ]
  },
  "updated": "2026-11-02",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 29,
    "unreachable": 0,
    "caveats": 11,
    "note": "Values read from pages fetched in this run. Crystran and Korth Kristalle disagree on several values (melting point, bulk modulus, dielectric direction, maximum temperature, specific heat); both are kept with their own sources."
  },
  "sources": {
    "crystran-quartz-page": {
      "title": "Crystal Quartz SiO2, product data page, Crystran Ltd",
      "url": "https://www.crystran.com/optical-materials/crystal-quartz-sio2/",
      "kind": "datasheet",
      "license": "supplier web page, cited not reproduced"
    },
    "crystran-quartz-datasheet": {
      "title": "Quartz Crystal (SiO2) data sheet, Crystran Ltd (PDF)",
      "url": "https://www.crystran.com/wp-content/uploads/2025/09/quartz-crystal-sio2-data-sheet.pdf",
      "year": 2025,
      "kind": "datasheet",
      "license": "supplier document, cited not reproduced"
    },
    "crystran-quartz-sds": {
      "title": "Safety Data Sheet: Quartz (SiO2) Optical Crystal, Crystran Ltd",
      "id": "revision 2016, issued 12 October 2016",
      "url": "https://www.crystran.com/wp-content/uploads/2025/09/quartz-crystal-sio2-msds.pdf",
      "year": 2016,
      "kind": "datasheet",
      "license": "supplier document, cited not reproduced"
    },
    "korth-quartz": {
      "title": "SiO2 Quartz Crystal, Korth Kristalle GmbH material page",
      "url": "https://www.korth.de/en/materials/detail/Quartz%20Crystal",
      "kind": "datasheet",
      "license": "supplier web page, cited not reproduced"
    },
    "usgs-mcs2026-quartz": {
      "title": "Mineral Commodity Summaries 2026: Quartz (high-purity and industrial cultured crystal)",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-quartz.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "nasa-ntrs-19920018076": {
      "title": "Study of factors determining the radiation sensitivity of quartz crystal oscillators (A0189), Second LDEF Post-Retrieval Symposium abstracts",
      "id": "NTRS 19920018076",
      "url": "https://ntrs.nasa.gov/citations/19920018076",
      "year": 1992,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "pubchem-silica": {
      "title": "PubChem compound record, Silica (CID 24261), GHS classification",
      "id": "CID 24261",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/24261",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "wikipedia-quartz": {
      "title": "Quartz (Wikipedia article)",
      "url": "https://en.wikipedia.org/wiki/Quartz",
      "kind": "web",
      "license": "CC BY-SA 4.0 (Wikipedia), cited for composition and history only"
    },
    "ntp-silica": {
      "title": "Report on Carcinogens, Fifteenth Edition: Silica, Crystalline (Respirable Size), National Toxicology Program",
      "url": "https://ntp.niehs.nih.gov/ntp/roc/content/profiles/silica.pdf",
      "kind": "report",
      "license": "public domain (NTP)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/crystal-quartz/"
}