Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Charnockite is a variety of granite containing minerals like orthopyroxene, quartz, and feldspar
History
Origin
-
Tamil Nadu, India
Discoverer
Unknown
T. H. Holland
Etymology
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
From Job Charnock, an administtrator of East India Company
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock