Definition
It is a metamorphic magnesium rich rock because it is composed of the mineral talc
A ganister is a hard, fine-grained quartzose sandstone or orthoquartzite which is basically used in the manufacture of silica brick typically used to line furnaces and is a type of sedimentary rocks.
History
Origin
USA
England
Discoverer
Unknown
Unknown
Etymology
From 17th century, because of its greasy feel and use like a soap
From gan′is-ter i.e a hard, close-grained siliceous stone, often forming the stratum which underlies a coal-seam
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock