Definition
Appinite is an igneous rock in which the crystals are so fine grained that individual minerals cannot be easily distinguished
Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate
History
Origin
-
-
Discoverer
Unknown
Unknown
Etymology
From the variety of Lamprophyre Greek lampros bright and shining + porphureos purple
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
Plutonic
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Other Categories
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock