igneous
Pegmatite with Quartz and Feldspar
Intrusive Igneous Rock
AI-generated identification · may be incorrectHardness: 6-7 on Mohs scale (due to quartz and feldspar components). Color: Mixed white, pink, reddish-brown, and grey. Luster: Vitreous to pearly on crystal faces. Crystal structure: Pegmatitic, characterized by exceptionally large, interlocking crystals. Cleavage: Good in feldspars, none in quartz.…
- Hardness
- 6-7 on Mohs scale (due to quartz and feldspar components)
- Color
- Mixed white, pink, reddish-brown, and grey
- Luster
- Vitreous to pearly on crystal faces
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Physical properties
Hardness: 6-7 on Mohs scale (due to quartz and feldspar components). Color: Mixed white, pink, reddish-brown, and grey. Luster: Vitreous to pearly on crystal faces. Crystal structure: Pegmatitic, characterized by exceptionally large, interlocking crystals. Cleavage: Good in feldspars, none in quartz. Specific gravity: ~2.6-2.7.
Formation & geological history
Formed from the crystallization of magma rich in water and other volatile elements during the final stages of magmatic crystallization, allowing massive crystal growth. Geological age varies widely depending on the specific pluton, ranging from Precambrian to Cenozoic.
Uses & applications
Source of industrial minerals, rare earth elements, gemstone mining (such as tourmaline, beryl, and topaz), and architectural stone.
Geological facts
Pegmatites often host some of the largest individual crystals ever found on Earth, sometimes measuring several meters in length.
Field identification & locations
Easily identified in the field by its very coarse-grained texture, featuring distinct large crystals of quartz, alkali feldspar, and micas. Commonly found in association with large continental granitic plutons worldwide.
