Definition
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Travertine is a mineral consisting of layered calcium carbonate formed by deposition from spring waters
History
Origin
USA
Italy
Discoverer
John Peter Salley
Marcus Vitruvius Pollio
Etymology
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
From Italian travertino a kind of building stone, from Tiburs, adjective from Tibur (Tivoli), in Italy
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock