Double-Chain and Layer Silicates Mineral Formula Comm Flashcards
1
Q
Anthophyllite
A
Mg7Si8O22(OH)2
- green/blue/deep grey colour
- long tabular crystals organized in different directions
- some criss-crossed stibs
2
Q
Cummingtonite
A
(Mg, Fe)7Si8O22(OH)2
- thin, stibby crystals that fan out radially
- partial fan of crystals
- black
3
Q
Tremolite
A
Ca2Mg5Si8O22(OH)2
- similar to petrified wood, not smooth and crystals mildly overlap (bone)
- can easily break; very soft
- sandy brown colour, long thin, tabular crystals
4
Q
Actinolite
A
Ca2(Mg, Fe)5Si8O22(OH)2
- glassy luster
- black, thin sheets (stibby) piled on top of each other
- some hand samples have tabular black/green crystals
5
Q
Hornblende
A
NaCa2(Mg, Fe)4Al(Al2Si6)O22(OH)2
- very similar to pyroxenes but different cleavage angles
- black
- tilt the mineral until you see the plane ith the layers
- slight gleam when tilted
6
Q
Glaucophane
A
Na2Mg3Al2Si8O22(OH)2
- glistens in the sun
- gold flakes stand out from black rock
7
Q
Kaolinite
A
Al4Si4O10(OH)2
- very soft, like chalk
- leaves white shit all over your hands
8
Q
Pyrophyllite
A
Al2Si4O10(OH)2
- white, lumpy
- Look closely and you can see thin, stibby crystals that radiate outwards, like a snowflake
9
Q
Muscovite
A
KAl2(AlSi3)O10(OH)2
- off white, transparent sheets that piled on top of each other
- flakes off easily
10
Q
Talc
A
Mg3Si4O10(OH)2
- very soft (hardness of 1)
- soapstone
- white
- greasy feeling
11
Q
Biotite
A
K(Mg, Fe, Al)3(Al, Si)4O10(OH)2
- black, green transparent sheets piled on to pof each other
- easy to break off sheets
12
Q
Antigorite
(Serpentine)
A
Mg6Si4O10(OH)8
- mildy soapy feeling
- penny will scratch it
- green (serpent) with asbestos layers
- smooth layers
13
Q
Chrysotile
A
Mg6Si4O10(OH)8
- blue/green
- white, silky fibers coming off of it
14
Q
Chlorite
A
(Mg, Fe, Al)6(Al, Si)4O10(OH)8
- green, black sheets cemented together
- pearly luster
- feels smooth but not soapy
