Definition
Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
History
Origin
Finland, Europe
USA
Discoverer
Jakob Sederholm
John Peter Salley
Etymology
From Finnish Rapakivi which stands for crumbly rock
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Plutonic
-
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock