igneous
Quartz-rich pegmatite, possibly with mica and feldspar
Granitic pegmatite; mainly quartz (SiO₂), feldspar, and biotite/muscovite mica
AI-generated identification · may be incorrectCoarse-grained, irregular interlocking crystals with pink-orange feldspar, gray-white quartz, and dark reflective mica. Quartz has Mohs hardness 7 and vitreous luster; feldspar is hardness 6–6.5 with cleavage, while mica shows prominent sheet cleavage; density is typically 2.6–2.8 g/cm³.
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Physical properties
Coarse-grained, irregular interlocking crystals with pink-orange feldspar, gray-white quartz, and dark reflective mica. Quartz has Mohs hardness 7 and vitreous luster; feldspar is hardness 6–6.5 with cleavage, while mica shows prominent sheet cleavage; density is typically 2.6–2.8 g/cm³.
Formation & geological history
Formed when silica- and water-rich magma cooled very slowly in late-stage veins, allowing exceptionally large crystals to grow. Pegmatites are generally Precambrian to Phanerozoic and commonly intrude granitic or metamorphic terranes.
Uses & applications
Used as a source of feldspar, quartz, mica, lithium, and rare-element minerals; attractive pieces are sold as display specimens, though this example appears primarily ornamental rather than gem quality.
Geological facts
The orange color likely reflects potassium feldspar stained by iron oxides, while the glittering dark flakes are mica. Pegmatites can host tourmaline, beryl, garnet, spodumene, and other collectible minerals.
Field identification & locations
Identify it by its very coarse texture, pink feldspar, glassy quartz, and flaky mica; common localities include Brazil, Madagascar, the United States, Canada, and Scandinavia. Confirm minerals with a streak, hardness, and cleavage test.
