Granite
Rock made of quartz, orthoclase, mica, plagioclase
Common
A coarse-grained rock of quartz, alkali feldspar, mica and plagioclase, white, pink or grey and peppered with dark biotite or hornblende. Massive and tough, it is the most abundant basement rock under the thin sedimentary veneer of the continents.
Rock
- Kind of rock
- Plutonic igneous rock
- Rock family
- Granite
- Texture
- coarse-grained, porphyritic (large crystals in a fine groundmass)
- Also contains
- Hornblende
- Deposits
- Hydrothermal vein (lode), Skarn, Pegmatite deposit
- Shapes the land into
- Mountain, Hill, Inselberg
- How it forms
- Magma rich in silica and alkalis cools slowly underground, in intrusions from dikes a few centimetres wide to batholiths hundreds of square kilometres across.
- Uses
- A construction stone throughout history, worked as far back as Ancient Egypt; today dimension stone and countertops.
Crystallography
- Habits
- Granular, Massive
Physical properties
- Density
- 2.7 g/cm³
- Luster
- Vitreous
- Colors
- white, pink, gray
- Transparency
- Opaque
Geology
- Origins
- Igneous
- Geography
- worldwide, Egypt, India, China, Brazil
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- Granite. Wikipedia.
- M. R. Gillespie, M. T. Styles, BGS Rock Classification Scheme, Volume 1: Classification of igneous rocks (Research Report RR 99-06). British Geological Survey, 1999.
Browse the Crystal Encyclopedia — MGS Toolbox