igneous
Pegmatite (Quartz and Feldspar)
Igneous Pegmatite containing SiO2 and KAlSi3O8
Hardness of 6-7 on Mohs scale, colors ranging from milky white and pink to greenish patches (likely due to weathering/lichen), vitreous to pearly luster, coarse-grained crystal structure, conchoidal fracture for quartz portions.
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Physical properties
Hardness of 6-7 on Mohs scale, colors ranging from milky white and pink to greenish patches (likely due to weathering/lichen), vitreous to pearly luster, coarse-grained crystal structure, conchoidal fracture for quartz portions.
Formation & geological history
Formed from the cooling of silica-rich magma deep within the Earth's crust, often during the final stages of magmatic crystallization, resulting in exceptionally large crystals.
Uses & applications
Used as a source of industrial minerals, rare earth elements, gemstone mining, and as collector specimens.
Geological facts
Pegmatites are famous for hosting some of the largest individual crystals ever found on Earth, including giant crystals of spodumene and beryl.
Field identification & locations
Easily identified by its extremely coarse, interlocking crystal grains of quartz and feldspar, often found in association with large batholiths and granitic intrusions.
