Talc
| Colour | White, Green, Gray |
|---|---|
| Mohs hardness | 1 (defining mineral) |
| Lustre | Waxy or pearly |
| Streak | White jot to pearl black |
| Crystal system | Monoclinic or triclinic |
| Transparency | Translucent |
| Cleavage | Perfect on {001} basal cleavage |
| Fracture | Flat surfaces (not cleavage), fracture in an uneven pattern |
| Specific gravity | 2.58–2.83 |
What is Talc?
Talc, or talcum, is a clay mineral composed of hydrated magnesium silicate, with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paints, and roofing material. It is a main ingredient in many cosmetics. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form.
How to identify Talc
- Lustre: Waxy or pearly.
- Hardness: Mohs 1 (defining mineral) — soft; a knife will scratch it.
- Streak: White jot to pearl black.
- Habit: Monoclinic or triclinic crystal system.
Talc in different forms
Stones often confused with Talc
Frequently asked questions
How hard is Talc?
Talc is Mohs 1 (defining mineral) on the hardness scale.
What colour is Talc?
Talc is typically white, green, gray (Light to dark green, brown, white, grey, colorless).