Definition
Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase
Taconite is a low-grade iron ore which belongs to sedimentary rock and containing about 27% iron and 51% silica
History
Origin
Finland, Europe
Western Australia, Minnesota
Discoverer
Jakob Sederholm
Newton Horace Winchell
Etymology
From Finnish Rapakivi which stands for crumbly rock
From the name of Taconic Mountains in New England
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
-
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock