Chalk
Chalk is a rock with the chemical formula CaCO₃. It has a Mohs hardness of 1-2 (Mohs scale) and dull to earthy luster.
Chalk properties
| Type | Rock |
|---|---|
| Chemical formula | CaCO₃ |
| Mohs hardness | 1-2 (Mohs scale) |
| Luster | dull to earthy |
| Typical colors | white, light gray, yellowish |
| Formation | formed from the accumulation of microscopic marine organisms' calcareous remains |
| Rarity | 3 / 10 |
Mohs hardness 1–2 — very soft
1 · Talc5 · Apatite10 · Diamond
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