metamorphic
Schist
Chlorite/Mica Schist
Hardness: 3.5–4 on Mohs scale; Color: Grayish-green to tan; Luster: Pearly to sub-metallic; Crystal Structure: Predominantly platy/foliated; Cleavage: Perfect schistosity along layers; Specific Gravity: 2.7–2.8.
- Hardness
- 3
- Color
- Grayish-green to tan
- Luster
- Pearly to sub-metallic
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Physical properties
Hardness: 3.5–4 on Mohs scale; Color: Grayish-green to tan; Luster: Pearly to sub-metallic; Crystal Structure: Predominantly platy/foliated; Cleavage: Perfect schistosity along layers; Specific Gravity: 2.7–2.8.
Formation & geological history
Formed from the metamorphism of clay-rich sedimentary rocks (shales) or igneous rocks under medium pressure and temperature. The greenish tint suggests greenschist facies metamorphism.
Uses & applications
Used as decorative stone, occasionally in construction for cladding, or as garden pathway gravel. It is not generally a high-value industrial mineral.
Geological facts
The word schist is derived from the Greek word 'schízein' meaning 'to split', referring to how easily the rock can be split along its plates. Schist contains a high percentage of platy minerals like mica and chlorite.
Field identification & locations
Identify by its 'schistosity'—the layered appearance of aligned mineral grains that sparkle in the light. In the field, look for thin, flaky layers that can often be peeled off with a knife.
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