Definition
Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
History
Origin
Finland, Europe
USA
Discoverer
Jakob Sederholm
Unknown
Etymology
From Finnish Rapakivi which stands for crumbly rock
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
-
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock