Definition
Foidolite is a rare type of coarse-grained intrusive igneous rock with a feldspathoid mineral content greater than 60%
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
History
Origin
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Discoverer
Unknown
Johann Gottlob Lehmann
Etymology
From the mineral feldspathoid which is the main content of rock
From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
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Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock