Definition
Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with minor pyroxene. It is an olivine-rich anorthosite, or a pyroxene-depleted relative of gabbro
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
Christian Leopold von Buch
Johann Gottlob Lehmann
Etymology
From German Troklotit, from Greek trōktēs, a marine fish (taken to be trout)
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, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
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Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock