{
  "spore": "profile",
  "id": "steatite",
  "spore_version": "0.2",
  "family": "oxide-ceramics",
  "name": "Steatite",
  "abbreviation": "MgO-SiO2",
  "role": "electrical insulator ceramic",
  "category": "ceramics",
  "type": "oxides",
  "summary": "Steatite, also called magnesium silicate ceramic, is made mostly from talc (soapstone) that is shaped and fired at about 1300 °C into a white or brown, non-flammable electrical insulator. Kyocera's white grade SO210O has a density of 2.8 g/cm3, a flexural strength of 190 MPa and a dielectric strength of 18 kV/mm, and Du-Co rates steatite for safe operating temperatures up to 1000 °C. A 2016 study of talc-based steatite measured a dielectric constant of about 5 to 8 and losses of 0.001 to 0.003 at 1 MHz. Two related insulating ceramics are cordierite (Kyocera CO220O: density 2.5 g/cm3, dielectric constant 4.9, expansion 1.5 ppm/K from 40 to 400 °C) and forsterite (Kyocera F1023O: density 3.0 g/cm3, dielectric constant 6.5, expansion 10.1 ppm/K). No space, vacuum or flight result for steatite was found in a source we could open.\n",
  "best_for": "Low-cost electrical insulators and heater supports that must not burn and must hold their shape to about 930 °C (Farnell glazed standoff rating)",
  "weakest_at": "Shear and torsion loads, and sudden changes in temperature; steatite is weak in shear, as are glass-type materials (RIKO and Farnell sheet)",
  "identity": {
    "formula": "MgO SiO2 (magnesium silicate; the fired body is mostly protoenstatite, MgSiO3)",
    "designations": [],
    "source": "kyocera-so210o",
    "where": "Specifications table, Chemical formula: MgO SiO2; Chemical name: Steatite"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "extreme-heat"
    ],
    "applications": [
      "electronics-and-chips",
      "thermal-control"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, white thermal-insulator grade (SO210O)",
      "value": 2.8,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1634",
        "form": "dense sintered steatite, water absorption 0"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Density row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, dark brown light-shield grade (SO211O)",
      "value": 3.1,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO211O, dark brown steatite",
        "test": "JIS R 1634",
        "form": "dense sintered steatite"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so211o",
      "where": "Mechanical and physical characteristics (typ.) table, Density row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO211O steatite datasheet (dark brown, good light shield)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO211O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, grade L-3",
      "value": 2.5,
      "bound": "exact",
      "unit": "g/cc",
      "scope": "material",
      "conditions": {
        "grade": "Du-Co steatite grade L-3",
        "form": "off-white, impervious to water"
      },
      "method": "Typical value from a manufacturer product page",
      "status": "ground",
      "source": "du-co-steatite",
      "where": "Material grade table, Density (g/cc) row, L-3 column",
      "source_detail": {
        "title": "Du-Co Ceramics: Steatite Ceramic, Magnesium Silicate (grades L-3 and L-5)",
        "id": "Du-Co Ceramics Company, Saxonburg PA",
        "url": "https://www.du-co.com/materials/steatite-magnesium-silicate/",
        "year": 2026,
        "kind": "web",
        "license": "manufacturer web page, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, grade L-5",
      "value": 2.7,
      "bound": "exact",
      "unit": "g/cc",
      "scope": "material",
      "conditions": {
        "grade": "Du-Co steatite grade L-5",
        "form": "off-white, impervious to water"
      },
      "method": "Typical value from a manufacturer product page",
      "status": "ground",
      "source": "du-co-steatite",
      "where": "Material grade table, Density (g/cc) row, L-5 column",
      "source_detail": {
        "title": "Du-Co Ceramics: Steatite Ceramic, Magnesium Silicate (grades L-3 and L-5)",
        "id": "Du-Co Ceramics Company, Saxonburg PA",
        "url": "https://www.du-co.com/materials/steatite-magnesium-silicate/",
        "year": 2026,
        "kind": "web",
        "license": "manufacturer web page, cited not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength, white grade (SO210O)",
      "value": 190,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1601, three-point bending",
        "form": "dense sintered steatite"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Flexural strength row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "flexural_strength",
      "label": "Flexural strength, dark brown grade (SO211O)",
      "value": 220,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO211O, dark brown steatite",
        "test": "JIS R 1601, three-point bending",
        "form": "dense sintered steatite"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so211o",
      "where": "Mechanical and physical characteristics (typ.) table, Flexural strength row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO211O steatite datasheet (dark brown, good light shield)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO211O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, white grade (SO210O)",
      "value": 120,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1602"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Young's modulus row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson's ratio, white grade (SO210O)",
      "value": 0.22,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1602"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Poisson's ratio row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Vickers hardness, white grade (SO210O)",
      "value": 5.8,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1610, HV 9.807 N load"
      },
      "method": "Typical value from a manufacturer datasheet; not a canonical property name, so vickers_hardness is used (see gaps)",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Vickers hardness row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Thermal expansion, white grade, 40 to 400 °C (SO210O)",
      "value": 7.7,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1618",
        "temperature_range": "40 to 400 °C"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Coefficient of linear thermal expansion, 40 to 400 °C row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Thermal expansion, white grade, 40 to 800 °C (SO210O)",
      "value": 8,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1618",
        "temperature_range": "40 to 800 °C"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Coefficient of linear thermal expansion, 40 to 800 °C row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Thermal expansion, dark brown grade, 40 to 400 °C (SO211O)",
      "value": 9.2,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO211O, dark brown steatite",
        "test": "JIS R 1618",
        "temperature_range": "40 to 400 °C"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so211o",
      "where": "Mechanical and physical characteristics (typ.) table, Coefficient of linear thermal expansion, 40 to 400 °C row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO211O steatite datasheet (dark brown, good light shield)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO211O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, white grade (SO210O)",
      "value": 2,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1611",
        "temperature": "not printed"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Thermal conductivity row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity, white grade (SO210O)",
      "value": 0.75,
      "bound": "exact",
      "unit": "J/(g·K)",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS R 1611",
        "unit_in_source": "J/(g*K)"
      },
      "method": "Typical value from a manufacturer datasheet; printed in J/(g*K) and left in that unit for import",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Specific heat capacity row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "dielectric_strength",
      "label": "Dielectric strength, white grade (SO210O)",
      "value": 18,
      "bound": "exact",
      "unit": "kV/mm",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS C 2141"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Dielectric strength row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant, white grade (SO210O)",
      "value": 6,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "grade": "Kyocera SO210O, white steatite",
        "test": "JIS C 2141",
        "frequency": "not printed"
      },
      "method": "Typical value from a manufacturer datasheet",
      "status": "ground",
      "source": "kyocera-so210o",
      "where": "Mechanical and physical characteristics (typ.) table, Dielectric constant row",
      "source_detail": {
        "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
        "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
        "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
        "year": 2023,
        "kind": "datasheet",
        "license": "manufacturer datasheet, cited not reproduced"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant, talc-based steatite fired at 1275 to 1300 °C",
      "value": 5,
      "value_high": 8,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 MHz",
        "temperature": "room temperature",
        "sintering": "2 h at 1275 °C (about 8) and 1300 °C (about 5)",
        "body": "talc, clay and dolomite, dry pressed"
      },
      "method": "Range read from the abstract, not a single value; lower end is the 1300 °C firing",
      "status": "ground",
      "source": "makovsek2016",
      "where": "Abstract, final sentences",
      "source_detail": {
        "title": "Processing of steatite ceramic with a low dielectric constant and low dielectric losses",
        "id": "Makovšek K., Ramšak I., Malič B., Bobnar V., Kuščer D., Informacije MIDEM Vol 46 No 2 (2016)",
        "url": "https://ojs.midem-drustvo.si/index.php/InfMIDEM/article/view/217",
        "year": 2016,
        "kind": "paper",
        "license": "journal article, cited not reproduced"
      }
    },
    {
      "benchmark": "dissipation_factor",
      "label": "Dielectric loss, talc-based steatite fired at 1275 to 1300 °C",
      "value": 0.001,
      "value_high": 0.003,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "frequency": "1 MHz",
        "temperature": "room temperature",
        "body": "talc, clay and dolomite, dry pressed"
      },
      "method": "Range read from the abstract",
      "status": "ground",
      "source": "makovsek2016",
      "where": "Abstract, final sentence",
      "source_detail": {
        "title": "Processing of steatite ceramic with a low dielectric constant and low dielectric losses",
        "id": "Makovšek K., Ramšak I., Malič B., Bobnar V., Kuščer D., Informacije MIDEM Vol 46 No 2 (2016)",
        "url": "https://ojs.midem-drustvo.si/index.php/InfMIDEM/article/view/217",
        "year": 2016,
        "kind": "paper",
        "license": "journal article, cited not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Continuous safe operating temperature, glazed L-5 steatite standoff",
      "value": 930,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Grade L-5 steatite, glazed, threaded standoffs",
        "form": "ceramic standoff"
      },
      "method": "Continuous safe operating rating printed on the distributor sheet",
      "status": "ground",
      "source": "farnell-standoff",
      "where": "Product notes, bullet on continuous safe operating temperature rating",
      "source_detail": {
        "title": "Farnell ceramic standoffs, grade L-5 steatite, glazed, fired at high temperature (product 2621193)",
        "id": "Farnell datasheet 2621193",
        "url": "https://www.farnell.com/datasheets/2621193.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "distributor document, linked not reproduced"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Continuous use temperature, unglazed C 220 connector housing",
      "value": 200,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "Steatite C 220, IEC 672-1, unglazed connector housing",
        "form": "terminal block housing with brass inserts"
      },
      "method": "Maximum continuous use temperature printed on the connector sheet; a second RIKO sheet prints 350 °C for a different connector with a glazed or similar housing",
      "status": "ground",
      "source": "riko-steatite-connector",
      "where": "Technical data table, continuous use temperature row",
      "source_detail": {
        "title": "RIKO Components steatite connector technical data, C 220 (Farnell datasheet 1564577)",
        "id": "RIKO Components GmbH, Farnell datasheet 1564577",
        "url": "https://www.farnell.com/datasheets/1564577.pdf",
        "year": 2026,
        "kind": "datasheet",
        "license": "distributor document, linked not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Chemicals and corrosive media, no test conditions given",
      "headline": "The steatite maker says it has very good corrosion resistance, but gives no test figures.",
      "effect": "Kyocera describes steatite as having high insulating capacity, good mechanical strength and high chemical resistance, and says it is used in the chemical industry for its corrosion resistance. No acid, alkali or immersion test data were found for steatite in a source we could open.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative manufacturer statement",
        "test": "none stated"
      },
      "source": "kyocera-steatite-page",
      "where": "Steatite section, description paragraph"
    },
    {
      "environment": "Moisture and water, dense steatite",
      "headline": "Dense steatite absorbs almost no water, with water absorption of 0.00 to 0.02 per cent.",
      "effect": "Du-Co lists steatite grades L-3 and L-5 as impervious to water, with water absorption of 0.00 to 0.02 per cent.",
      "rating": "none",
      "conditions": {
        "grades": "L-3 and L-5",
        "test": "not printed",
        "basis": "manufacturer typical value"
      },
      "source": "du-co-steatite",
      "where": "Physical properties table, Water Absorption row"
    },
    {
      "environment": "Heat over long periods, dimensional stability",
      "headline": "Steatite stays dimensionally stable up to about 1000 °C, according to two suppliers.",
      "effect": "Du-Co gives safe operating temperatures up to 1000 °C for steatite in general, and the RIKO sheet says the material is dimensionally stable up to about 1000 °C. Neither source reports a long-term ageing test, and the RIKO sheet limits the surrounding temperature to 200 °C where brass inserts are used.",
      "rating": "low",
      "conditions": {
        "basis": "supplier statements",
        "duration": "not stated"
      },
      "source": "riko-steatite-connector",
      "where": "Other properties section, dimensional stability line"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "The steatite supplier sheet treats unfired steatite as an article with no health hazard under normal use, and classifies it as not a hazardous substance or mixture under GHS. Health effects are relevant only when dust is made during machining.",
        "ghs": [],
        "source": "stc-sds-steatite",
        "where": "Sections 2 and 4"
      },
      {
        "text": "The USGS summary of talc says that an ECHA committee in July 2025 recommended classifying talc as a Category 1B carcinogen (H350) and as STOT RE 1 (H372). This is an opinion, not an adopted classification, and it concerns talc, the main raw material of steatite.",
        "ghs": [
          "H350",
          "H372"
        ],
        "source": "usgs-mcs2026-talc",
        "where": "Domestic Production and Use section, final paragraph on the ECHA opinion"
      }
    ],
    "failure_risks": [
      {
        "mode": "Brittle failure under shear or torsion",
        "trigger": "Shear or torsion load on a steatite part, such as a twisted standoff or a threaded insulator",
        "consequence": "The distributor says steatite is strong in compression and tension but weak in shear (torsion), as are all glass-type materials, so the part can break without warning.",
        "severity": "moderate",
        "source": "farnell-standoff",
        "where": "Product notes, first bullet"
      },
      {
        "mode": "Overheating past the rating",
        "trigger": "Surrounding temperature above 200 °C in a connector with brass inserts",
        "consequence": "The RIKO sheet says that above this limit the brass inserts reach their scaling temperature.",
        "severity": "moderate",
        "source": "riko-steatite-connector",
        "where": "Other properties section"
      },
      {
        "mode": "Dust from machining",
        "trigger": "Grinding or machining steatite without dust control",
        "consequence": "The supplier sheet says the dust contains crystalline silica and can irritate the eyes, nose, throat and skin.",
        "severity": "low",
        "source": "stc-sds-steatite",
        "where": "Section 4, general advice"
      }
    ],
    "side_effects": [
      {
        "text": "Metal inserts in a steatite connector housing (brass, nickel-plated) scale at high temperature; the RIKO sheet limits the surrounding temperature to 200 °C to keep them below their scaling temperature.",
        "affects": "Brass or nickel-plated inserts in the housing",
        "source": "riko-steatite-connector",
        "where": "Other properties section"
      }
    ],
    "handling": [
      {
        "text": "Wet mop or dry vacuum dust from machining; the supplier sheet recommends local or general exhaust ventilation where dust is made.",
        "source": "stc-sds-steatite",
        "where": "Sections 6, 7 and 8"
      },
      {
        "text": "For the unfired powder the organic portion is combustible and the flash point is printed as 220 °C; the sheet lists a possible Class A fire hazard from vapour in the headspace above the product.",
        "source": "stc-sds-steatite",
        "where": "Sections 5 and 9"
      }
    ],
    "mitigations": [
      {
        "text": "Ask the supplier for specified values for critical parts; Kyocera prints its values as typical and says they vary with product configuration and manufacturing process.",
        "source": "kyocera-so210o",
        "where": "Footnote below the mechanical and physical characteristics table"
      }
    ]
  },
  "uses": [
    {
      "application": "electronics-and-chips",
      "device": "Terminal-block housings and insulating connector bodies (ground use, not flown)",
      "example": "RIKO Components sells steatite (C 220, IEC 672-1, unglazed) connector housings with nominal voltages printed as 250 V and 450 V, depending on the number of poles.",
      "source": "riko-steatite-connector",
      "where": "Electrical values table, nominal voltage column"
    },
    {
      "application": "thermal-control",
      "device": "Band heater insulators, heater supports and thermocouple parts (ground use)",
      "example": "Du-Co lists steatite for electrical heating equipment, insulators, thermocouples and sensors, with safe operating temperatures up to 1000 °C.",
      "source": "du-co-steatite",
      "where": "Steatite Ceramic page, introduction paragraph"
    },
    {
      "application": "thermal-control",
      "device": "Threaded ceramic standoffs for heated assemblies (ground use)",
      "example": "A distributor sells glazed grade L-5 steatite standoffs with a continuous safe operating temperature rating of 930 °C (1700 °F).",
      "source": "farnell-standoff",
      "where": "Product notes, bullet on continuous safe operating temperature"
    },
    {
      "application": "electronics-and-chips",
      "device": "Various circuit parts, white thermal-insulator grade (ground industrial use)",
      "example": "Kyocera lists its white steatite SO210O for various circuit parts and as a thermal insulator.",
      "source": "kyocera-so210o",
      "where": "Specifications table, Main applications"
    }
  ],
  "supply": [
    {
      "subject": "Talc (steatite is about 90 per cent soapstone, which is talc)",
      "producers": [
        {
          "country": "India (steatite)",
          "share_percent": 21.7,
          "year": 2025
        },
        {
          "country": "China (unspecified minerals)",
          "share_percent": 18.8,
          "year": 2025
        },
        {
          "country": "Brazil (crude and beneficiated)",
          "share_percent": 8.3,
          "year": 2025
        },
        {
          "country": "United States (crude)",
          "share_percent": 7.1,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: Recycling: Insignificant.",
      "substitutes": [
        "USGS: substitutes for talc in ceramics include bentonite, chlorite, feldspar, kaolin and pyrophyllite."
      ],
      "source": "usgs-mcs2026-talc",
      "where": "World Mine Production and Reserves table, 2025e (world total 6900 thousand t; shares calculated by Space Mushroom against that total, so they are not exact national shares of steatite alone); Salient Statistics; Recycling; Substitutes. Pakistan supplied 52 per cent of US talc imports in 2021 to 2024 (Import Sources)."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Kyocera Fineceramics Europe SO210O steatite datasheet",
      "type": "datasheet",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
      "year": 2023
    },
    {
      "title": "Kyocera Fineceramics Europe SO211O steatite datasheet",
      "type": "datasheet",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO211O.pdf",
      "year": 2023
    },
    {
      "title": "Makovšek et al., Processing of steatite ceramic with a low dielectric constant and low dielectric losses (Informacije MIDEM)",
      "type": "paper",
      "url": "https://ojs.midem-drustvo.si/index.php/InfMIDEM/article/view/217",
      "year": 2016
    },
    {
      "title": "Mineral Commodity Summaries 2026: Talc and pyrophyllite",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-talc.pdf",
      "year": 2026
    },
    {
      "title": "Superior Technical Ceramics safety data sheet: Unfired Steatite (rev. 03/22/2024)",
      "type": "sds",
      "url": "https://ceramics.net/wp-content/uploads/STC-SDS-Unfired-Steatite-Rev-03-22-2024.pdf",
      "year": 2024
    },
    {
      "title": "Kyocera Fineceramics Europe CO220O cordierite datasheet (related ceramic)",
      "type": "datasheet",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/cordierit/Kyocera_Fineceramics_Europe_CO220O.pdf",
      "year": 2023
    },
    {
      "title": "Kyocera Fineceramics Europe F1023O forsterite datasheet (related ceramic)",
      "type": "datasheet",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/forsterit/Kyocera_Fineceramics_Europe_F1023O.pdf",
      "year": 2023
    },
    {
      "title": "Farnell ceramic standoffs, grade L-5 steatite (product 2621193)",
      "type": "datasheet",
      "url": "https://www.farnell.com/datasheets/2621193.pdf",
      "year": 2026
    },
    {
      "title": "RIKO Components steatite connector technical data, C 220 (Farnell datasheet 1564577)",
      "type": "datasheet",
      "url": "https://www.farnell.com/datasheets/1564577.pdf",
      "year": 2026
    }
  ],
  "gaps": [
    "No space, vacuum, radiation, outgassing or flight result for steatite or talc-based ceramics was found in a source we could open; the uses listed are ground and industrial.",
    "No numeric acid, alkali, humidity or long-term ageing test for steatite was found. The corrosion entry rests on Kyocera's qualitative statement; a cordierite membrane acid and alkali study (Dong et al., 2007) could not be opened.",
    "Vickers hardness is not a canonical property name; it is entered as vickers_hardness.",
    "Kyocera's steatite page calls the material porous, while its datasheets call the grades dense sintered; this conflict is not resolved here.",
    "The dielectric loss and loss factor printed for the SO211O grade (750 and 6000 in the 10^-4 units) look implausible for a steatite and were not entered.",
    "The dielectric constant at the Kyocera datasheets is printed without a frequency (JIS C 2141 standard only); the 1 MHz values come from the MIDEM paper.",
    "The melting point of steatite (enstatite-type MgSiO3) was not read on a fetched page and is not entered.",
    "No UNS, EN or DIN designation for steatite was printed on a source read in this run. RIKO prints IEC 672-1 class C 220, but IEC is not one of the designation systems in the schema.",
    "The IPS Ceramics and Elan Technology steatite datasheets could not be opened (404 and bot-block), and the MakeItFrom pages returned a cookie wall, so their values are not used.",
    "The PubChem talc hazard record could not be opened in this run (the REST lookup returned a different compound), so GHS hazard data rest on the supplier sheet and the USGS summary of the ECHA opinion.",
    "Critical-mineral listing of talc (USGS 2025 list and EU critical raw materials list) was not checked.",
    "Cordierite and forsterite are not profiled here; their numbers come from the Kyocera CO220O and F1023O datasheets and appear in the summary and story only as related ceramics."
  ],
  "story": {
    "why": "Steatite, also called magnesium silicate ceramic, is one of the most widely used technical ceramic materials (Du-Co). It is made mostly from talc, or soapstone, which the distributor puts at about 90 per cent; the powder is shaped and fired at roughly 1300 °C with additives. The result is a dense, white or brown solid that insulates well and holds its shape at high temperature. Its limits are mechanical: it is weak in shear and torsion, as glass-type materials are, and it cracks rather than bends. Its appeal is cost and insulation. The space record is empty: no vacuum, radiation or flight data for steatite were found in a source we could open.",
    "uses": [
      {
        "where": "Electrical connectors and terminal blocks",
        "line": "RIKO Components sells steatite C 220 connector housings with nominal voltages printed as 250 V and 450 V, depending on the number of poles. These are ground products, not flight hardware."
      },
      {
        "where": "Heater insulators and heater supports",
        "line": "Du-Co lists steatite for electrical heating equipment, insulators, thermocouples and sensors, with safe operating temperatures up to 1000 °C. A distributor rates its glazed grade L-5 standoffs at 930 °C continuous safe operation."
      },
      {
        "where": "Circuit parts",
        "line": "Kyocera lists its white steatite SO210O for various circuit parts and as a thermal insulator."
      }
    ],
    "can_do": [
      {
        "label": "Electrical insulation",
        "line": "The white grade SO210O has a dielectric strength of 18 kV/mm and a dielectric constant of 6, both typical values from the Kyocera datasheet under JIS C 2141.",
        "scope": "material",
        "value": "18 kV/mm"
      },
      {
        "label": "Low loss at radio frequency",
        "line": "A 2016 study of talc-based steatite, fired at 1275 to 1300 °C, measured dielectric losses of 0.001 to 0.003 at 1 MHz, and a dielectric constant that fell from about 8 to about 5 as the firing temperature rose.",
        "scope": "material",
        "value": "0.001 to 0.003"
      },
      {
        "label": "Heat",
        "line": "A glazed grade L-5 standoff has a continuous safe operating rating of 930 °C, and steatite is dimensionally stable up to about 1000 °C according to two suppliers.",
        "scope": "material",
        "value": "930 °C"
      },
      {
        "label": "Stiffness and strength",
        "line": "The white grade has a flexural strength of 190 MPa and a Young's modulus of 120 GPa; the dark brown grade reaches 220 MPa.",
        "scope": "material",
        "value": "190 MPa"
      }
    ],
    "compare": "Du-Co calls steatite cost-effective, and its density runs from 2.5 to 3.1 g/cm3 depending on grade. Cordierite (Kyocera CO220O) is about as dense at 2.5 g/cm3, has a dielectric constant of 4.9 and expands only 1.5 ppm/K from 40 to 400 °C. Forsterite (Kyocera F1023O) is denser at 3.0 g/cm3, has a dielectric constant of 6.5 and expands 10.1 ppm/K, which Kyocera markets as high thermal expansion. Steatite, at 7.7 ppm/K, lies between the two.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Thermal expansion",
        "benchmark": "cte",
        "scope": "material"
      },
      {
        "label": "Dielectric strength",
        "benchmark": "dielectric_strength",
        "scope": "material"
      }
    ],
    "handling": [
      "Wet mop or dry vacuum dust from machining, and use local exhaust ventilation where dust is made.",
      "Ask the supplier for specified values for critical parts, because the values quoted are typical.",
      "Keep the continuous temperature below the rating for the grade, and below 200 °C where brass inserts are used."
    ],
    "good_for": [
      "Cheap, non-flammable electrical insulation. The white grade has a dielectric strength of 18 kV/mm.",
      "Heater insulation and standoffs. A glazed grade L-5 standoff is rated to 930 °C for continuous use."
    ],
    "watch_out": [
      "Shear and torsion loads. Steatite is weak in shear, as glass-type materials are.",
      "Metal inserts. Brass inserts scale above 200 °C in the RIKO connector housing.",
      "Machining dust. The dust contains crystalline silica, and talc is under ECHA review as a carcinogen.",
      "No space record. No vacuum, radiation or flight result for steatite was found in a source we could open."
    ],
    "verdict": "Steatite is a low-cost, non-flammable insulator for electrical parts and heater supports up to about 930 °C. It is weak in shear and torsion, and no space test data were found.",
    "recipe": {
      "line": "Steatite is a magnesium silicate ceramic. Its raw material, talc, is a hydrated magnesium silicate; during firing the body forms mainly protoenstatite, which is an MgSiO3 phase, with a glassy phase between the grains.",
      "parts": [
        {
          "name": "Magnesium",
          "symbol": "Mg",
          "role": "The main metal in the body. Talc supplies it, and it sits in the enstatite-type MgSiO3 phase that gives steatite its insulating character."
        },
        {
          "name": "Silicon",
          "symbol": "Si",
          "role": "Bonded to oxygen in silicate groups. Silicon and oxygen make up the rigid crystal and the glassy phase between the grains."
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Completes the silicate groups. Oxygen is the element that makes the body an oxide ceramic."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The supplier classes unfired steatite as not a hazardous substance, but grinding or machining produces dust that can irritate, and the ECHA talc opinion is a risk to note for the raw mineral.",
        "points": [
          {
            "label": "The solid",
            "line": "A supplier sheet for unfired steatite classifies it as not a hazardous substance or mixture under GHS, and treats it as an article with no health hazard under normal use."
          },
          {
            "label": "Dust",
            "line": "Dust from machining can contain crystalline silica and irritate the eyes, nose, throat and skin. Wet mopping or dry vacuuming is recommended."
          },
          {
            "label": "Talc opinion",
            "line": "In July 2025 an ECHA committee recommended classing talc as a Category 1B carcinogen (H350) and as STOT RE 1 (H372). This is an opinion, not a final classification of steatite."
          }
        ],
        "level": 0,
        "verdict": "Not hazardous under normal use; dust is the concern"
      },
      {
        "title": "If a part fails in service",
        "lead": "These limits come from supplier data sheets, not from incidents in service.",
        "points": [
          {
            "label": "Shear and torsion",
            "line": "Steatite is strong in compression and tension but weak in shear (torsion), as are all glass-type materials. A twisted standoff can break without warning."
          },
          {
            "label": "Temperature limits",
            "line": "A glazed grade L-5 standoff is rated for continuous safe operation at 930 °C. A C 220 connector housing is rated to 200 °C, because the brass inserts scale above that temperature."
          },
          {
            "label": "Fire",
            "line": "Fired steatite is described as non-flammable (RIKO). The unfired powder's safety sheet notes a combustible organic part and a flash point of 220 °C."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 20,
    "unreachable": 3,
    "caveats": 2,
    "note": "Written by an AI assistant on 2026-10-26 from manufacturer datasheets, one open journal paper and the USGS 2026 talc chapter read in this run. Three sources could not be opened (IPS Ceramics, Elan Technology, MakeItFrom). Caveats: the Kyocera SO211O loss values were left out as implausible, and the Kyocera sheets give no test frequency for the dielectric constant."
  },
  "sources": {
    "kyocera-so210o": {
      "title": "Kyocera Fineceramics Europe SO210O steatite datasheet (white, thermal insulator)",
      "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO210O.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "manufacturer datasheet, cited not reproduced"
    },
    "kyocera-so211o": {
      "title": "Kyocera Fineceramics Europe SO211O steatite datasheet (dark brown, good light shield)",
      "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/steatit/Kyocera_Fineceramics_Europe_SO211O.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "manufacturer datasheet, cited not reproduced"
    },
    "kyocera-co220o": {
      "title": "Kyocera Fineceramics Europe CO220O dense sintered cordierite datasheet",
      "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/cordierit/Kyocera_Fineceramics_Europe_CO220O.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "manufacturer datasheet, cited not reproduced"
    },
    "kyocera-f1023o": {
      "title": "Kyocera Fineceramics Europe F1023O dense sintered forsterite datasheet",
      "id": "Kyocera Fineceramics Europe GmbH, datasheet dated 2023.04.03",
      "url": "https://www.kyocera-fineceramics.de/fileadmin/user_upload/Download/werkstoffdatenblaetter/forsterit/Kyocera_Fineceramics_Europe_F1023O.pdf",
      "year": 2023,
      "kind": "datasheet",
      "license": "manufacturer datasheet, cited not reproduced"
    },
    "kyocera-steatite-page": {
      "title": "Kyocera Fineceramics Europe: Steatite material page",
      "id": "kyocera-fineceramics.de/en/materials/steatite",
      "url": "https://www.kyocera-fineceramics.de/en/materials/steatite",
      "year": 2026,
      "kind": "web",
      "license": "manufacturer web page, cited not reproduced"
    },
    "du-co-steatite": {
      "title": "Du-Co Ceramics: Steatite Ceramic, Magnesium Silicate (grades L-3 and L-5)",
      "id": "Du-Co Ceramics Company, Saxonburg PA",
      "url": "https://www.du-co.com/materials/steatite-magnesium-silicate/",
      "year": 2026,
      "kind": "web",
      "license": "manufacturer web page, cited not reproduced"
    },
    "makovsek2016": {
      "title": "Processing of steatite ceramic with a low dielectric constant and low dielectric losses",
      "id": "Makovšek K., Ramšak I., Malič B., Bobnar V., Kuščer D., Informacije MIDEM Vol 46 No 2 (2016)",
      "url": "https://ojs.midem-drustvo.si/index.php/InfMIDEM/article/view/217",
      "year": 2016,
      "kind": "paper",
      "license": "journal article, cited not reproduced"
    },
    "usgs-mcs2026-talc": {
      "title": "Mineral Commodity Summaries 2026: Talc and Pyrophyllite",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-talc.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "stc-sds-steatite": {
      "title": "Superior Technical Ceramics safety data sheet: Unfired Steatite (hydrated magnesium silicate)",
      "id": "STC SDS, last revision 03/22/2024",
      "url": "https://ceramics.net/wp-content/uploads/STC-SDS-Unfired-Steatite-Rev-03-22-2024.pdf",
      "year": 2024,
      "kind": "datasheet",
      "license": "supplier document, linked not reproduced"
    },
    "farnell-standoff": {
      "title": "Farnell ceramic standoffs, grade L-5 steatite, glazed, fired at high temperature (product 2621193)",
      "id": "Farnell datasheet 2621193",
      "url": "https://www.farnell.com/datasheets/2621193.pdf",
      "year": 2026,
      "kind": "datasheet",
      "license": "distributor document, linked not reproduced"
    },
    "riko-steatite-connector": {
      "title": "RIKO Components steatite connector technical data, C 220 (Farnell datasheet 1564577)",
      "id": "RIKO Components GmbH, Farnell datasheet 1564577",
      "url": "https://www.farnell.com/datasheets/1564577.pdf",
      "year": 2026,
      "kind": "datasheet",
      "license": "distributor document, linked not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/steatite/"
}