Igneous
Granitic Pegmatite with Tourmaline/Chlorite
Pegmatite
Coarse-grained texture, consisting of quartz (white/gray, hardness 7), feldspar (white/pink/tan, hardness 6), and dark green to black minerals likely chlorite or tourmaline. Luster varies from vitreous to dull.
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Physical properties
Coarse-grained texture, consisting of quartz (white/gray, hardness 7), feldspar (white/pink/tan, hardness 6), and dark green to black minerals likely chlorite or tourmaline. Luster varies from vitreous to dull.
Formation & geological history
Formed during the final stages of a magma body's crystallization. The slow cooling and high water content allow for the growth of exceptionally large crystals.
Uses & applications
Often mined for industrial minerals like feldspar and quartz, and occasionally for rare earth elements or gemstones like tourmaline, beryl, or topaz.
Geological facts
Pegmatites are famous for hosting some of the largest crystals ever found, sometimes measuring several meters in length.
Field identification & locations
Identified by its extremely coarse grain size compared to typical granite. Commonly found in regions with significant granitic intrusions. Collectors often search pegmatite outcrops for gem-quality minerals.
