Definition
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Eclogite is an extreme metamorphic rock, formed by regional metamorphism of basalt rock under very high pressure and temperature
History
Origin
USA
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Discoverer
John Peter Salley
René Just Haüy
Etymology
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
From French, Greek eklogē selection with reference to the selective content of the rock + -ite1
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
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Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock