Phyllosilicates - Flat Sheets With Infinite Extent

Phyllosilicates - Flat Sheets With Infinite Extent 

Serpentine Mg3(OH),SiA Type B + silicate layer on one side l Serpentines are commonly greenish yellow and have a greasy or silky luster and a slightly soapy feel 

Talc Mg3(OH),(Si,05)3 Type B + silicate on both sides Very soft, light green or yellow mineral with a soapy or greasy feel. Can be cut with a knife 

Pyrophyllite Al,(0H),(Si205)2 Type A + silicate on both sides ) The mineral occurs foliated or in compact masses The color is gray to brown 

Biotite (black mica) K(Mg,Fe)3(OH)j (AlSijOjQ) Type B + silicate on both sides. Substituted talc )) A black, brown, or dark green, foliated mineral, more common than muscovite ) 

---