Definition
Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase
Metapelite is an old and currently not widely used field geological term for a clay rich fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone
History
Origin
Finland, Europe
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Discoverer
Jakob Sederholm
Unknown
Etymology
From Finnish Rapakivi which stands for crumbly rock
From Pelos or clay in Greek
Class
Igneous Rocks
Metamorphic 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
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock