Definition
Origin
Discoverer
Etymology
Class
Sub-Class
Group
Other Categories
Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals
From Greek pegma, pegmat which means- thing joined together + -ite
Coarse Grained Rock, Opaque Rock
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Fine Grained Rock, Opaque Rock