The softest known mineral, defining hardness 1 on the Mohs scale. Has a soapy feel and is the main component of soapstone. Color: White, green, gray. Luster: Pearly to greasy. Streak: White. Cleavage: Perfect basal. Hardness: 1. Transparency: Translucent. Crystal system: Monoclinic. Chemical formula: Mg₃Si₄O₁₀ OH ₂. Specific gravity: 2.7-2.8. Formation: Forms from hydrothermal alteration of magnesium-rich minerals like olivine and pyroxene in ultramafic rocks. Common geological settings: Worldwide; Italy, India, Brazil, USA; found in metamorphosed dolomites and ultramafic rocks. Common look-alikes and related entries: Pyrophyllite, Brucite, Soapstone.
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
Editorial owner
GeoMiner
Last updated
2026-03-30T14:36:52.901051+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
The softest known mineral, defining hardness 1 on the Mohs scale. Has a soapy feel and is the main component of soapstone.
How can you identify Talc?
Compare several properties rather than relying on colour alone. This entry records colour: White, green, gray; lustre: Pearly to greasy; streak: White; Mohs hardness: 1; cleavage: Perfect basal; crystal system: Monoclinic; transparency: Translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Talc form?
Forms from hydrothermal alteration of magnesium-rich minerals like olivine and pyroxene in ultramafic rocks.
Where is Talc commonly found?
Worldwide; Italy, India, Brazil, USA; found in metamorphosed dolomites and ultramafic rocks.
What is Talc commonly confused with?
Talc may be confused with Pyrophyllite, Brucite, Soapstone. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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