Definition
It is a metamorphic magnesium rich rock because it is composed of the mineral talc
Basaltic Trachyandesite is an extrusive igneous rock which is a type of Basalt rock and is formed by the rapid cooling of basaltic lava exposed at or very near the Earth's surface
History
Origin
USA
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Discoverer
Unknown
Unknown
Etymology
From 17th century, because of its greasy feel and use like a soap
From its mineral and compound content and its relation with Basalt and Andesite rock
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
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Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock