Definition
Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster
Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase
History
Origin
Pennsylvania, U.S.
Finland, Europe
Discoverer
Unknown
Jakob Sederholm
Etymology
From Greek anthrakites, from anthrax, anthrak meaning coal
From Finnish Rapakivi which stands for crumbly rock
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
-
Plutonic
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock