igneous
Pegmatite
Igneous Pegmatite
AI-generated identification · may be incorrectExtremely coarse-grained with interlocking crystals often larger than 2.5 cm. Hardness varies by mineral content (quartz is 7, feldspar is 6, mica is 2-2.5). Color is typically light, composed of quartz, alkali feldspar, and muscovite.
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Physical properties
Extremely coarse-grained with interlocking crystals often larger than 2.5 cm. Hardness varies by mineral content (quartz is 7, feldspar is 6, mica is 2-2.5). Color is typically light, composed of quartz, alkali feldspar, and muscovite.
Formation & geological history
Formed from the water-rich residual melts of crystallizing magmas deep within the Earth's crust, cooling slowly during the final stages of magmatic crystallization.
Uses & applications
A primary source for rare-earth elements, lithium minerals, industrial gemstones, and high-purity quartz used in electronics.
Geological facts
Pegmatites can host some of the largest individual mineral crystals ever found on Earth, sometimes measuring several meters in length.
Field identification & locations
Identified easily by its extremely large crystal sizes compared to surrounding rocks. Found worldwide in major mountain belts and ancient cratons.
