Definition
Origin
Discoverer
Etymology
Class
Sub-Class
Group
Other Categories
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Oolite is a sedimentary rock formed from ooids, spherical grains which are composed of concentric layers of calcite
From oo- + -lite, after German Oolit. A rock consisting of fine grains of carbonate of lime
Durable Rock, Medium Hardness Rock
Fine Grained Rock, Opaque Rock