Definition
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat
History
Origin
Adak, Aleutian Islands
France
Discoverer
Defant and Drummond
Unknown
Etymology
From Adak, Aleutian Islands
From French, Latin lignum wood + -ite1
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
Volcanic
-
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock