igneous
Pegmatite (Quartz with Tourmaline/Biotite inclusions)
Igneous Pegmatite
Hardness of 7 on the Mohs scale (due to quartz), color is translucent white/yellowish with dark black mineral inclusions, vitreous to greasy luster, massive to crystalline structure, conchoidal fracture, specific gravity around 2.65.
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Physical properties
Hardness of 7 on the Mohs scale (due to quartz), color is translucent white/yellowish with dark black mineral inclusions, vitreous to greasy luster, massive to crystalline structure, conchoidal fracture, specific gravity around 2.65.
Formation & geological history
Formed from the extreme final stage of crystallization of magma, often rich in water and other volatile elements, resulting in very large crystals. Found globally in continental crust and mountain-building zones.
Uses & applications
Source of rare-earth elements, gemstone mining, mineral collecting, and ceramic/glass manufacturing raw materials.
Geological facts
Pegmatites are famous for hosting some of the largest individual crystals ever found on Earth, including giant crystals of spodumene, beryl, and tourmaline.
Field identification & locations
Easily identified by its extremely coarse-grained texture where individual mineral crystals are visibly much larger than in typical granite. Commonly found in association with granitic plutons worldwide.
