{
  "spore": "profile",
  "id": "gemstones-technical",
  "spore_version": "0.2",
  "family": "optical-crystals",
  "name": "Technical gemstone minerals (beryl, opal, turquoise, feldspar, olivine)",
  "abbreviation": "Be3Al2Si6O18 / SiO2 / CuAl6(PO4)4(OH)8 / KAlSi3O8 / (Mg,Fe)2SiO4",
  "role": "gem-quality minerals used as hard, transparent or decorative crystal material; beryl is also a beryllium feedstock",
  "category": "glasses-optics",
  "type": "optical-crystals",
  "summary": "Five gem minerals, grouped because they are sold and studied as crystal or mineral material rather than as single compounds: beryl (emerald is its green chromium-bearing form), opal (amorphous hydrated silica), turquoise (a hydrated copper aluminium phosphate), orthoclase feldspar (the family that includes moonstone) and olivine (peridot is its magnesium-rich form). The Handbook of Mineralogy gives beryl a Mohs hardness of 7.5 to 8 and a measured density of 2.63 to 2.97 g/cm3, with an ordinary refractive index of 1.567 to 1.610. Turquoise is softer, at 5 to 6, and orthoclase is 6 to 6.5. Opal has the lowest density of the set, at 1.9 to 2.3 g/cm3, with a refractive index of 1.43. Goodfellow's search and gemstones pages read in this run list none of these minerals, so this file does not claim that Goodfellow sells them. Values are kept with the source that prints each one.\n",
  "best_for": "Hard, transparent mineral material where hardness and density matter (beryl and forsterite are the hardest, at Mohs 7 to 8)",
  "weakest_at": "Brittleness and cleavage: the Handbook lists beryl, orthoclase and forsterite as brittle, and orthoclase cleaves perfectly on two planes. Opal and turquoise are softer, at Mohs 5 to 6",
  "identity": {
    "formula": "Be3Al2Si6O18 (beryl); CuAl6(PO4)4(OH)8 4H2O (turquoise); SiO2 with water (opal); KAlSi3O8 (orthoclase); (Mg,Fe)2SiO4 (olivine); Mg2SiO4 (forsterite)",
    "crystal_system": "beryl hexagonal; turquoise triclinic; orthoclase monoclinic; olivine orthorhombic; opal amorphous (no crystals)",
    "designations": [],
    "source": "hom-beryl",
    "where": "Crystal Data row of the beryl, turquoise, orthoclase and forsterite Handbook entries; olivine and opal from the webmineral Olivine and Opal pages (Crystallography sections)"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "structures",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density of beryl, measured range",
      "value": 2.63,
      "value_high": 2.97,
      "bound": "range",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "beryl (Be3Al2Si6O18), including emerald",
        "note": "Handbook says density increases with alkali content; average 2.7"
      },
      "method": "Range printed in the Handbook of Mineralogy beryl entry",
      "status": "ground",
      "source": "hom-beryl",
      "where": "Physical Properties paragraph, D(meas.) value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy beryl data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of beryl, calculated",
      "value": 2.64,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "beryl (Be3Al2Si6O18)"
      },
      "method": "Calculated value printed in the Handbook of Mineralogy beryl entry",
      "status": "calculated",
      "source": "hom-beryl",
      "where": "Physical Properties paragraph, D(calc.) value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy beryl data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "label": "Hardness of beryl",
      "value": 7.5,
      "value_high": 8,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "beryl (Be3Al2Si6O18)",
        "scale": "Mohs (the Handbook prints the hardness without naming the scale)"
      },
      "method": "Range printed in the Handbook of Mineralogy beryl entry",
      "status": "ground",
      "source": "hom-beryl",
      "where": "Physical Properties paragraph, Hardness row",
      "source_detail": {
        "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy beryl data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of beryl, ordinary ray (omega)",
      "value": 1.567,
      "value_high": 1.61,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "beryl (Be3Al2Si6O18)",
        "wavelength": "not stated in the entry",
        "note": "Handbook says the index increases with alkali content"
      },
      "method": "Range printed in the Handbook of Mineralogy beryl entry",
      "status": "ground",
      "source": "hom-beryl",
      "where": "Optical Properties paragraph (omega printed as a symbol garbled in the text read)",
      "source_detail": {
        "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy beryl data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of beryl, extraordinary ray (epsilon)",
      "value": 1.565,
      "value_high": 1.599,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "beryl (Be3Al2Si6O18)",
        "wavelength": "not stated in the entry"
      },
      "method": "Range printed in the Handbook of Mineralogy beryl entry",
      "status": "ground",
      "source": "hom-beryl",
      "where": "Optical Properties paragraph (epsilon printed as a symbol garbled in the text read)",
      "source_detail": {
        "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy beryl data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of turquoise, measured",
      "value": 2.86,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "turquoise (CuAl6(PO4)4(OH)8 4H2O)",
        "note": "Handbook says less when massive"
      },
      "method": "Value printed in the Handbook of Mineralogy turquoise entry",
      "status": "ground",
      "source": "hom-turquoise",
      "where": "Physical Properties paragraph, D(meas.) value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy turquoise data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
        "year": 2005,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "label": "Hardness of turquoise",
      "value": 5,
      "value_high": 6,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "turquoise",
        "scale": "Mohs (the Handbook prints the hardness without naming the scale)"
      },
      "method": "Range printed in the Handbook of Mineralogy turquoise entry",
      "status": "ground",
      "source": "hom-turquoise",
      "where": "Physical Properties paragraph, Hardness row",
      "source_detail": {
        "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy turquoise data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
        "year": 2005,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of turquoise, alpha",
      "value": 1.61,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "turquoise",
        "wavelength": "not stated in the entry"
      },
      "method": "Value printed in the Handbook of Mineralogy turquoise entry",
      "status": "ground",
      "source": "hom-turquoise",
      "where": "Optical Properties paragraph, alpha value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy turquoise data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
        "year": 2005,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of turquoise, beta",
      "value": 1.62,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "turquoise",
        "wavelength": "not stated in the entry"
      },
      "method": "Value printed in the Handbook of Mineralogy turquoise entry",
      "status": "ground",
      "source": "hom-turquoise",
      "where": "Optical Properties paragraph, beta value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy turquoise data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
        "year": 2005,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of turquoise, gamma",
      "value": 1.65,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "turquoise",
        "wavelength": "not stated in the entry"
      },
      "method": "Value printed in the Handbook of Mineralogy turquoise entry",
      "status": "ground",
      "source": "hom-turquoise",
      "where": "Optical Properties paragraph, gamma value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy turquoise data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
        "year": 2005,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of opal, range",
      "value": 1.9,
      "value_high": 2.3,
      "bound": "range",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "opal (SiO2 with water)",
        "note": "the page gives an average of 2.09 g/cm3"
      },
      "method": "Range printed on the webmineral opal page (Physical Properties)",
      "status": "ground",
      "source": "webmineral-opal",
      "where": "Physical Properties of Opal, density range",
      "source_detail": {
        "title": "webmineral: Opal data page",
        "id": "webmineral.com/data/Opal.shtml (page undated)",
        "url": "https://webmineral.com/data/Opal.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "label": "Hardness of opal",
      "value": 5.5,
      "value_high": 6,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "opal",
        "scale": "Mohs (the webmineral page compares it to a knife blade and orthoclase)"
      },
      "method": "Range printed on the webmineral opal page",
      "status": "ground",
      "source": "webmineral-opal",
      "where": "Physical Properties of Opal, Hardness row",
      "source_detail": {
        "title": "webmineral: Opal data page",
        "id": "webmineral.com/data/Opal.shtml (page undated)",
        "url": "https://webmineral.com/data/Opal.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of opal",
      "value": 1.43,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "opal",
        "optical_class": "isotropic"
      },
      "method": "Value printed on the webmineral opal page",
      "status": "ground",
      "source": "webmineral-opal",
      "where": "Optical Properties of Opal, isotropic n value",
      "source_detail": {
        "title": "webmineral: Opal data page",
        "id": "webmineral.com/data/Opal.shtml (page undated)",
        "url": "https://webmineral.com/data/Opal.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of orthoclase, measured range",
      "value": 2.55,
      "value_high": 2.63,
      "bound": "range",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "orthoclase (KAlSi3O8), the feldspar family that includes moonstone",
        "note": "moonstone is an adularia variety; the Handbook orthoclase entry does not name moonstone"
      },
      "method": "Range printed in the Handbook of Mineralogy orthoclase entry",
      "status": "ground",
      "source": "hom-orthoclase",
      "where": "Physical Properties paragraph, D(meas.) value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy orthoclase data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "label": "Hardness of orthoclase",
      "value": 6,
      "value_high": 6.5,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "orthoclase",
        "scale": "Mohs (the Handbook prints the hardness without naming the scale)"
      },
      "method": "Range printed in the Handbook of Mineralogy orthoclase entry",
      "status": "ground",
      "source": "hom-orthoclase",
      "where": "Physical Properties paragraph, Hardness row",
      "source_detail": {
        "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy orthoclase data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of orthoclase, alpha",
      "value": 1.518,
      "value_high": 1.52,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "orthoclase",
        "wavelength": "not stated in the entry"
      },
      "method": "Range printed in the Handbook of Mineralogy orthoclase entry",
      "status": "ground",
      "source": "hom-orthoclase",
      "where": "Optical Properties paragraph, alpha value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy orthoclase data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of orthoclase, beta",
      "value": 1.522,
      "value_high": 1.524,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "orthoclase",
        "wavelength": "not stated in the entry"
      },
      "method": "Range printed in the Handbook of Mineralogy orthoclase entry",
      "status": "ground",
      "source": "hom-orthoclase",
      "where": "Optical Properties paragraph, beta value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy orthoclase data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of orthoclase, gamma",
      "value": 1.522,
      "value_high": 1.525,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "orthoclase",
        "wavelength": "not stated in the entry"
      },
      "method": "Range printed in the Handbook of Mineralogy orthoclase entry",
      "status": "ground",
      "source": "hom-orthoclase",
      "where": "Optical Properties paragraph, gamma value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy orthoclase data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Specific gravity of olivine, calculated",
      "value": 3.3,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "olivine group, (Mg,Fe)2SiO4"
      },
      "method": "Calculated value printed on the webmineral olivine page",
      "status": "calculated",
      "source": "webmineral-olivine",
      "where": "Calculated Properties of Olivine, Specific Gravity note",
      "source_detail": {
        "title": "webmineral: Olivine data page",
        "id": "webmineral.com/data/Olivine.shtml (page undated)",
        "url": "https://webmineral.com/data/Olivine.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "label": "Hardness of olivine",
      "value": 6.5,
      "value_high": 7,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "olivine group (peridot is a magnesium-rich member)",
        "scale": "Mohs (the webmineral page compares it to pyrite and quartz)"
      },
      "method": "Range printed on the webmineral olivine page",
      "status": "ground",
      "source": "webmineral-olivine",
      "where": "Physical Properties of Olivine, Hardness row",
      "source_detail": {
        "title": "webmineral: Olivine data page",
        "id": "webmineral.com/data/Olivine.shtml (page undated)",
        "url": "https://webmineral.com/data/Olivine.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of olivine, alpha",
      "value": 1.63,
      "value_high": 1.65,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "olivine group",
        "wavelength": "not stated on the page"
      },
      "method": "Range printed on the webmineral olivine page",
      "status": "ground",
      "source": "webmineral-olivine",
      "where": "Optical Properties of Olivine, Optical Data row (a)",
      "source_detail": {
        "title": "webmineral: Olivine data page",
        "id": "webmineral.com/data/Olivine.shtml (page undated)",
        "url": "https://webmineral.com/data/Olivine.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of olivine, gamma",
      "value": 1.67,
      "value_high": 1.69,
      "bound": "range",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "olivine group",
        "wavelength": "not stated on the page"
      },
      "method": "Range printed on the webmineral olivine page",
      "status": "ground",
      "source": "webmineral-olivine",
      "where": "Optical Properties of Olivine, Optical Data row (g)",
      "source_detail": {
        "title": "webmineral: Olivine data page",
        "id": "webmineral.com/data/Olivine.shtml (page undated)",
        "url": "https://webmineral.com/data/Olivine.shtml",
        "year": 2026,
        "kind": "web",
        "license": "secondary database page, linked not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of forsterite, measured",
      "value": 3.275,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "mineral": "forsterite (Mg2SiO4), the magnesium end member of the olivine series"
      },
      "method": "Value printed in the Handbook of Mineralogy forsterite entry",
      "status": "ground",
      "source": "hom-forsterite",
      "where": "Physical Properties paragraph, D(meas.) value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Forsterite (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy forsterite data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/forsterite.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "label": "Hardness of forsterite",
      "value": 7,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "forsterite",
        "scale": "Mohs (the Handbook prints the hardness without naming the scale)"
      },
      "method": "Value printed in the Handbook of Mineralogy forsterite entry",
      "status": "ground",
      "source": "hom-forsterite",
      "where": "Physical Properties paragraph, Hardness row",
      "source_detail": {
        "title": "Handbook of Mineralogy: Forsterite (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy forsterite data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/forsterite.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index of forsterite, gamma",
      "value": 1.67,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "mineral": "forsterite",
        "wavelength": "not stated in the entry"
      },
      "method": "Value printed in the Handbook of Mineralogy forsterite entry",
      "status": "ground",
      "source": "hom-forsterite",
      "where": "Optical Properties paragraph, gamma value",
      "source_detail": {
        "title": "Handbook of Mineralogy: Forsterite (Mineral Data Publishing)",
        "id": "Handbook of Mineralogy forsterite data sheet, PDF",
        "url": "https://handbookofmineralogy.org/pdfs/forsterite.pdf",
        "year": 2001,
        "kind": "handbook",
        "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
      }
    }
  ],
  "corrosion": [],
  "risks": {
    "hazards": [
      {
        "text": "USGS says beryllium is toxic, and that industry must control beryllium dust, fumes and mists in the workplace. Beryl is an imported beryllium feedstock, so it carries the same concern.",
        "ghs": [],
        "source": "usgs-beryllium-2026",
        "where": "Events, Trends, and Issues paragraph"
      }
    ],
    "failure_risks": [
      {
        "mode": "Brittle fracture",
        "trigger": "Impact or bending of a faceted or thin piece",
        "consequence": "The Handbook lists beryl, orthoclase and forsterite as brittle, so these crystals break rather than bend.",
        "severity": "moderate",
        "source": "hom-beryl",
        "where": "Physical Properties paragraph, Tenacity row"
      },
      {
        "mode": "Perfect cleavage in orthoclase",
        "trigger": "Stress along the cleavage planes",
        "consequence": "The Handbook gives perfect cleavage on the 001 and 010 planes, so the crystal splits along flat faces.",
        "severity": "moderate",
        "source": "hom-orthoclase",
        "where": "Physical Properties paragraph, Cleavage row"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Keep beryl dust, fumes and mists out of the workplace air, as the USGS notes that industry must control beryllium dust.",
        "source": "usgs-beryllium-2026",
        "where": "Events, Trends, and Issues paragraph"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "electronics-and-chips",
      "device": "Beryllium metal, oxide and beryllium-copper master alloy made from beryllium hydroxide (Utah plant)",
      "example": "USGS: consumer electronics took about 29% of beryllium product sales and semiconductor applications about 2%. Imported beryl was one feedstock for the beryllium hydroxide.",
      "source": "usgs-beryllium-2026",
      "where": "Domestic Production and Use paragraph"
    },
    {
      "application": "structures",
      "device": "Plate glass, ceramic tiles and sanitaryware, made with feldspar as a flux and raw material",
      "example": "USGS: feldspar is ground for glassmaking and for ceramics, where it works as a flux. Ceramics and pottery took 53% of domestic feldspar end use.",
      "source": "usgs-feldspar-2026",
      "where": "Domestic Production and Use paragraph; Events, Trends, and Issues paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Beryllium, world mine production 2025 estimate (metric tons of beryllium content)",
      "producers": [
        {
          "country": "United States",
          "share_percent": 53.5,
          "year": 2025
        },
        {
          "country": "Brazil",
          "share_percent": 18.6,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 17.9,
          "year": 2025
        },
        {
          "country": "Nigeria",
          "share_percent": 9.3,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: recovered from new and old scrap, which may be 20% to 25% of total beryllium consumption.",
      "substitutes": [
        "USGS: aluminum, silicon carbide, steel or titanium may replace beryllium metal in some uses, but the substitutes reduce performance.",
        "USGS: aluminum nitride or boron nitride may be substituted for beryllium oxide."
      ],
      "source": "usgs-beryllium-2026",
      "where": "World Mine Production and Reserves table, 2025e column (United States 230 tons, world total 430 rounded). Shares calculated by Space Mushroom as country value divided by the printed world total of 430 (rounded). The rows sum to 432, so the shares are approximate."
    },
    {
      "subject": "Feldspar, world mine production 2025 (thousand metric tons)",
      "producers": [
        {
          "country": "India",
          "share_percent": 19.4,
          "year": 2025
        },
        {
          "country": "Turkey",
          "share_percent": 17.1,
          "year": 2025
        },
        {
          "country": "Iran",
          "share_percent": 12.6,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 11.9,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: feldspar is not recycled by producers; container cullet reduces consumption of feldspar in glass.",
      "substitutes": [
        "USGS: imported nepheline syenite was the major alternative material for feldspar."
      ],
      "source": "usgs-feldspar-2026",
      "where": "World Mine Production and Reserves table, 2025 column. Shares calculated by Space Mushroom as country value divided by the printed world total of 31,000 thousand t (rounded). The rows do not sum exactly to the total."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing, 2001 to 2005 version)",
      "type": "database",
      "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
      "year": 2001
    },
    {
      "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
      "type": "database",
      "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
      "year": 2005
    },
    {
      "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
      "type": "database",
      "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
      "year": 2001
    },
    {
      "title": "Handbook of Mineralogy: Forsterite (Mineral Data Publishing)",
      "type": "database",
      "url": "https://handbookofmineralogy.org/pdfs/forsterite.pdf",
      "year": 2001
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Beryllium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-beryllium.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Feldspar and nepheline syenite",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-feldspar.pdf",
      "year": 2026
    }
  ],
  "gaps": [
    "Goodfellow: the search pages for beryl, emerald, opal, turquoise, moonstone, feldspar, peridot and olivine, and the Goodfellow gemstones category page, read in this run list none of these minerals. No Goodfellow product code, purity or form is given here, and the file does not claim Goodfellow sells them.",
    "Emerald: the beryl entry covers beryl, and emerald is its green chromium-bearing form. No emerald-specific value (colour, inclusions, chromium content) was read from a source in this run.",
    "Moonstone: no source read names moonstone. The orthoclase values are used as a proxy for the feldspar family. Moonstone's sheen (adularia) and its own density and index were not sourced.",
    "Peridot: the forsterite values are the magnesium end member. The olivine range from webmineral is a group range. Peridot's own composition, density and index were not sourced.",
    "Opal: the webmineral page gives density, hardness and index. No water content, dehydration or ageing data for opal was read.",
    "Corrosion or ageing: no corrosion, weathering or ageing source was read for any of the five minerals. The corrosion section is empty for that reason.",
    "Abrasive and substrate uses: no source read in this run names an abrasive or substrate use for beryl, opal, turquoise, feldspar or olivine. Sapphire and ruby are alumina crystals with their own profiles (sapphire.yaml and ruby.yaml); no values from them are reused here.",
    "Critical-mineral status for beryllium and feldspar was not checked against the USGS critical minerals list in this run.",
    "Refractive indices: the Handbook and webmineral pages do not give a wavelength, so the wavelength in conditions is marked as not stated.",
    "Hardness: the Handbook and webmineral pages print hardness without naming the scale. Mohs is assumed for the values as printed.",
    "Fracture toughness, thermal conductivity and thermal expansion for these five minerals were not found in the sources opened.",
    "The webmineral pages are a secondary database. The olivine and opal values were not checked against a primary paper."
  ],
  "story": {
    "why": "These five minerals are the gem minerals that a technical buyer would weigh for hardness, density and optical index. Beryl is the hardest at Mohs 7.5 to 8. Opal is the lightest, with a density of 1.9 to 2.3 g/cm3. Turquoise and opal are the softest, at Mohs 5 to 6. The Handbook and webmineral pages give the index for each mineral, and the USGS covers beryllium and feldspar supply.",
    "uses": [
      {
        "where": "Beryllium from beryl",
        "line": "USGS: beryllium products went mainly to consumer electronics (about 29%) and aerospace and defense (about 24%). Imported beryl was one feedstock for the beryllium hydroxide used to make metal and oxide."
      },
      {
        "where": "Feldspar for glass and ceramics",
        "line": "USGS: feldspar is a flux for plate glass, ceramic tiles and sanitaryware. Ceramics and pottery took 53% of domestic feldspar end use."
      }
    ],
    "can_do": [
      {
        "label": "Hardness",
        "line": "Beryl is at Mohs 7.5 to 8 in the Handbook of Mineralogy, the hardest of the five. Orthoclase is 6 to 6.5, and turquoise is 5 to 6.",
        "scope": "material",
        "value": "7.5 to 8"
      },
      {
        "label": "Density",
        "line": "Measured beryl density is 2.63 to 2.97 g/cm3. Opal is 1.9 to 2.3 g/cm3, and forsterite is 3.275 g/cm3.",
        "scope": "material",
        "value": "2.63 to 2.97 g/cm3"
      },
      {
        "label": "Refractive index",
        "line": "The ordinary refractive index of beryl is 1.567 to 1.610, and opal is isotropic at 1.43.",
        "scope": "material",
        "value": "1.567 to 1.610"
      },
      {
        "label": "Beryllium supply",
        "line": "World beryllium mine production was about 430 metric tons of beryllium content in 2025, with the United States at 230 tons.",
        "scope": "material",
        "value": "430 t"
      }
    ],
    "compare": "On the printed values, beryl is the hardest of the five minerals at Mohs 7.5 to 8, and forsterite (the magnesium end of the olivine series) is next at Mohs 7. Opal is the lightest, at 1.9 to 2.3 g/cm3. Beryl (2.63 to 2.97 g/cm3) is lighter than the olivine group (3.3) and forsterite (3.275), and turquoise (2.86) falls inside its range. Turquoise and opal are the softest. The sources read give no cost, availability or purity comparison between the minerals as crystal material, and none of them is sold by Goodfellow in the pages read.",
    "compare_rows": [
      {
        "label": "Hardness",
        "benchmark": "mohs_hardness",
        "scope": "material"
      },
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Refractive index",
        "benchmark": "refractive_index",
        "scope": "material"
      }
    ],
    "handling": [
      "Beryl is a beryllium mineral, so control dust and fumes from cutting or grinding, as the USGS says for beryllium.",
      "Orthoclase cleaves on two planes, so support faceted or thin pieces to avoid splitting along a cleavage.",
      "Turquoise and opal are softer than beryl, at Mohs 5 to 6, so avoid abrasive contact."
    ],
    "good_for": [
      "Hard, transparent mineral material where hardness matters: beryl at Mohs 7.5 to 8, and forsterite at Mohs 7.",
      "Beryllium feedstock: imported beryl converted to beryllium hydroxide, as the USGS describes.",
      "Glass and ceramic raw material: feldspar as a flux for plate glass and ceramic tiles."
    ],
    "watch_out": [
      "Brittleness: beryl, orthoclase and forsterite are brittle, and orthoclase has perfect cleavage.",
      "Softness: turquoise and opal are at Mohs 5 to 6, below beryl and orthoclase.",
      "Beryllium toxicity: beryl dust must be controlled.",
      "Source limits: no corrosion, ageing, fracture toughness or thermal data was read for these minerals."
    ],
    "verdict": "Beryl is the hardest and most useful for technical crystal work, with a clear beryllium-toxicity limit. Opal, turquoise and the feldspar and olivine minerals are useful as data points but have few technical uses in the sources read. Goodfellow does not list these minerals on the pages read in this run, so this file is a mineral data record, not a supplier listing. For the alumina crystals used as optics and substrates, see the sapphire and ruby profiles (sapphire.yaml and ruby.yaml).",
    "recipe": {
      "line": "The five minerals are not one compound. Beryl is a beryllium aluminium silicate, turquoise a hydrated copper aluminium phosphate, opal a hydrated silica, orthoclase a potassium aluminium silicate, and olivine a magnesium iron silicate. Each is a natural mineral, so the formula varies with the locality.",
      "parts": [
        {
          "name": "Beryllium",
          "symbol": "Be",
          "role": "The light metal in beryl and the source of beryllium metal and oxide."
        },
        {
          "name": "Aluminium",
          "symbol": "Al",
          "role": "Present in beryl, turquoise and orthoclase."
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "The main framework element of beryl, opal, orthoclase and olivine."
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Present in every silicate and phosphate."
        },
        {
          "name": "Copper",
          "symbol": "Cu",
          "role": "The colour-giving metal in turquoise."
        },
        {
          "name": "Magnesium and iron",
          "symbol": "Mg and Fe",
          "role": "The two cations that form the olivine series; peridot is the magnesium-rich end."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "USGS says beryllium is toxic and that industry must control its dust, fumes and mists. Beryl is a beryllium feedstock, so the same concern applies to beryl dust.",
        "points": [
          {
            "label": "Beryllium",
            "line": "USGS: beryllium is toxic, so workplace dust, fumes and mists must be controlled."
          },
          {
            "label": "Silica",
            "line": "Opal is a hydrated silica. No silica hazard was read in a source, so none is stated here."
          }
        ],
        "level": 1,
        "verdict": "Beryl carries beryllium toxicity risk"
      },
      {
        "title": "If it fails",
        "lead": "The failure facts come from the Handbook of Mineralogy entries, not from field incidents.",
        "points": [
          {
            "label": "Breaking",
            "line": "The Handbook lists beryl, orthoclase and forsterite as brittle, so they break rather than bend."
          },
          {
            "label": "Cleavage",
            "line": "Orthoclase cleaves perfectly on two planes, so a stressed crystal can split along flat faces."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Dust",
            "line": "Keep beryl dust out of the air in the workplace, as the USGS says for beryllium."
          }
        ],
        "gap": "No storage temperature or humidity limit was read for any of the five minerals."
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 27,
    "unreachable": 0,
    "caveats": 6,
    "note": "Written by an AI assistant on 2026-10-26 from pages and PDFs read in the same run. Goodfellow lists none of these minerals, so the file does not say it sells them. The olivine and opal values come from a secondary database. Moonstone and emerald are covered only through their parent minerals. The hardness scale is not named in the sources and is read as Mohs. No corrosion or ageing source was read."
  },
  "sources": {
    "hom-beryl": {
      "title": "Handbook of Mineralogy: Beryl (Mineral Data Publishing)",
      "id": "Handbook of Mineralogy beryl data sheet, PDF",
      "url": "https://handbookofmineralogy.org/pdfs/beryl.pdf",
      "year": 2001,
      "kind": "handbook",
      "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
    },
    "hom-turquoise": {
      "title": "Handbook of Mineralogy: Turquoise (Mineral Data Publishing)",
      "id": "Handbook of Mineralogy turquoise data sheet, PDF",
      "url": "https://handbookofmineralogy.org/pdfs/turquoise.pdf",
      "year": 2005,
      "kind": "handbook",
      "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
    },
    "hom-orthoclase": {
      "title": "Handbook of Mineralogy: Orthoclase (Mineral Data Publishing)",
      "id": "Handbook of Mineralogy orthoclase data sheet, PDF",
      "url": "https://handbookofmineralogy.org/pdfs/orthoclase.pdf",
      "year": 2001,
      "kind": "handbook",
      "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
    },
    "hom-forsterite": {
      "title": "Handbook of Mineralogy: Forsterite (Mineral Data Publishing)",
      "id": "Handbook of Mineralogy forsterite data sheet, PDF",
      "url": "https://handbookofmineralogy.org/pdfs/forsterite.pdf",
      "year": 2001,
      "kind": "handbook",
      "license": "Mineral Data Publishing, all rights reserved; linked, not reproduced"
    },
    "webmineral-olivine": {
      "title": "webmineral: Olivine data page",
      "id": "webmineral.com/data/Olivine.shtml (page undated)",
      "url": "https://webmineral.com/data/Olivine.shtml",
      "year": 2026,
      "kind": "web",
      "license": "secondary database page, linked not reproduced"
    },
    "webmineral-opal": {
      "title": "webmineral: Opal data page",
      "id": "webmineral.com/data/Opal.shtml (page undated)",
      "url": "https://webmineral.com/data/Opal.shtml",
      "year": 2026,
      "kind": "web",
      "license": "secondary database page, linked not reproduced"
    },
    "usgs-beryllium-2026": {
      "title": "USGS Mineral Commodity Summaries 2026: Beryllium",
      "id": "USGS MCS 2026, beryllium chapter",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-beryllium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-feldspar-2026": {
      "title": "USGS Mineral Commodity Summaries 2026: Feldspar and nepheline syenite",
      "id": "USGS MCS 2026, feldspar chapter",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-feldspar.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "goodfellow-gemstones": {
      "title": "Goodfellow: Gemstones category page and product search (beryl, emerald, opal, turquoise, feldspar, olivine searches)",
      "id": "goodfellow.com/usa/material/gemstones and goodfellow.com/search",
      "url": "https://www.goodfellow.com/usa/material/gemstones",
      "year": 2026,
      "kind": "web",
      "license": "supplier page, linked not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/gemstones-technical/"
}