igneous
Pegmatite
Igneous Pegmatite
Mohs hardness typically 6-7 for the overall rock (due to abundant quartz and feldspar); colors vary widely from white, grey, pink, to multicolored depending on mineral content; vitreous to pearly luster; coarse-grained to very coarse-grained crystal structure with crystals often exceeding several centimeters.
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Physical properties
Mohs hardness typically 6-7 for the overall rock (due to abundant quartz and feldspar); colors vary widely from white, grey, pink, to multicolored depending on mineral content; vitreous to pearly luster; coarse-grained to very coarse-grained crystal structure with crystals often exceeding several centimeters.
Formation & geological history
Formed from the water-rich, late-stage crystallization of magma deep within the Earth's crust, allowing large crystals to grow slowly over geological timescales.
Uses & applications
Source of rare earth elements, gem-quality minerals (like tourmaline, beryl, and topaz), industrial minerals like feldspar and quartz, and specimen collecting.
Geological facts
Pegmatites are famous for hosting some of the largest individual mineral crystals ever found on Earth, sometimes measuring several meters in length.
Field identification & locations
Easily identified in the field by its extremely coarse interlocking texture, where individual crystals of quartz, feldspar, and mica are exceptionally large compared to standard granite.
