Definition
Origin
Discoverer
Etymology
Class
Sub-Class
Group
Other Categories
Rhomb-porphyry is a porphyritic igneous rock with abundant wedge or lens shaped anorthoclase or feldspar phenocrysts
From Latin term that means purple
Durable Rock, Medium Hardness Rock
Fine 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