igneous
Rapakivi Granite
Alkali-feldspar granite
AI-generated identification · may be incorrectHardness 6 on Mohs scale; distinctive pink to red potassium feldspar ovoids surrounded by a ring of greenish-grey plagioclase or hornblende; vitreous luster.
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Physical properties
Hardness 6 on Mohs scale; distinctive pink to red potassium feldspar ovoids surrounded by a ring of greenish-grey plagioclase or hornblende; vitreous luster.
Formation & geological history
Formed through the slow cooling of magma deep within the Earth's crust during the Proterozoic eon, typically around 1.5 to 1.6 billion years ago.
Uses & applications
Commonly used as a durable dimension stone in architectural cladding, monuments, countertops, and high-end construction.
Geological facts
The name means 'crumbly rock' in Finnish because weathered specimens easily disintegrate into sand-sized mineral grains. It is the national rock of Finland.
Field identification & locations
Easily identified in the field by large, rounded pink feldspar crystals enveloped in a dark mafic matrix. Found extensively in the Fennoscandian Shield and North America.
