chlorite group
Sign in to saveAlso known as chlorite mineral group, chlorite
group of phyllosilicate minerals
Key facts
- Category
- Phyllosilicate minerals
- Formula
- (Mg,Fe) 3 (Si,Al) 4 O 10 (OH) 2 · (Mg,Fe) 3 (OH) 6
- Ima symbol
- Chl
- Crystal system
- Monoclinic 2/m; with some triclinic polymorphs.
- Color
- Various shades of green; rarely yellow, red, or white.
- Crystal habit
- Foliated masses, scaley aggregates, disseminated flakes.
- Cleavage
- Perfect 001
- Fracture
- Lamellar
- Mohs scale hardness
- 2–2.5
- Luster
- Vitreous, pearly, dull
- Streak
- Pale green to grey
- Specific gravity
- 2.6–3.3
- Refractive index
- 1.57–1.67
- Other characteristics
- Folia flexible – not elastic
via Wikipedia infobox
~6 min read
Encyclopedic overview
The chlorites are the group of phyllosilicate minerals common in low-grade metamorphic rocks and in altered igneous rocks.
Chlorite minerals do not contain the element chlorine. The name chlorite is from the Greek chloros (χλωρός), meaning "green", in reference to its color. Greenschist, formed by metamorphism of basalt or other low-silica volcanic rock, typically contains significant amounts of chlorite mineral (but not the chlorite ion, nor chlorine in any other form).
Excerpted from Wikipedia’s “chlorite group” article, available under the CC BY-SA 4.0 licence.