mineral

Talc (Soapstone variety)

Talc (Hydrated magnesium silicate) - Mg3Si4O10(OH)2

Hardness: 1 (Mohs scale); Color: White, pale green, or grey; Luster: Pearly to greasy; Crystal Structure: Monoclinic; Cleavage: Perfect basal; Specific Gravity: 2.7 to 2.8. It has a distinctive soapy feel.

Hardness: 1 (Mohs scale)
Color: White, pale green, or grey
Luster: Pearly to greasy

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the metamorphism of magnesian minerals (such as olivine, pyroxene, or amphibole) often in the presence of water and carbon dioxide. Common in regional metamorphic belts where ultramafic rocks are altered.

Uses & applications

Industry: Paper making, plastic, paint, and rubber filler. Cosmetics: Talcum powder. Construction: Sink tops and electrical switchboards (as soapstone). Art: Popular carving medium due to softness.

Geological facts

Talc is the softest known mineral on the Mohs scale, capable of being scratched by a fingernail. It is chemically inert and highly heat-resistant, which is why it is used in industrial laboratory tabletops.

Field identification & locations

Identify in the field by its extreme softness (scratches with a fingernail) and greasy feel. Often found in greenstone belts or associated with serpentine. Locations: USA (Appalachians), Brazil, China, and the Alps.

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