igneous
Quartz–feldspar pegmatite (probable)
Coarse-grained granitic pegmatite, mainly quartz and feldspar, with possible mica
AI-generated identification · may be incorrectThe specimen appears white to gray and unevenly crystalline, with glassy quartz and pale, blocky feldspar; mica may account for darker reflective patches. Quartz and feldspar are about Mohs 6–7; the photo does not establish exact mineral proportions or specific gravity.
Identified More igneous →
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Physical properties
The specimen appears white to gray and unevenly crystalline, with glassy quartz and pale, blocky feldspar; mica may account for darker reflective patches. Quartz and feldspar are about Mohs 6–7; the photo does not establish exact mineral proportions or specific gravity.
Formation & geological history
Pegmatite forms when the last, water-rich melt from cooling magma crystallizes slowly in veins and dikes, producing exceptionally large crystals. Its age cannot be determined from the image.
Uses & applications
Pegmatite is mined for feldspar, quartz, mica, and specialty elements; attractive pieces are collected, and individual crystals may be cut or polished.
Geological facts
Pegmatites can host very large crystals and rare minerals such as tourmaline, beryl, and spodumene.
Field identification & locations
Look for interlocking coarse crystals: quartz is typically glassy and lacks cleavage, feldspar is opaque with flat cleavage faces, and mica splits into shiny sheets. Common worldwide in granitic terrains; a close-up or simple hardness/cleavage tests would improve identification.
