igneous
Pegmatitic granite
Coarse-grained granite/pegmatite, chiefly quartz, feldspar, and mica
AI-generated identification · may be incorrectHardness about 6–7 Mohs; irregular coarse crystals with cream feldspar, translucent quartz, reddish iron-oxide staining, dark mica or amphibole; vitreous to pearly luster and poor cleavage overall, though feldspar shows cleavage.
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Physical properties
Hardness about 6–7 Mohs; irregular coarse crystals with cream feldspar, translucent quartz, reddish iron-oxide staining, dark mica or amphibole; vitreous to pearly luster and poor cleavage overall, though feldspar shows cleavage.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma, allowing exceptionally large interlocking crystals; likely Paleozoic to Precambrian in age depending on locality.
Uses & applications
Used as dimension stone, aggregate, countertops, and landscaping material; attractive pieces are collected, though this specimen has modest gem value.
Geological facts
The red-brown colors commonly reflect hematite or limonite alteration of iron-bearing minerals. Pegmatites can host tourmaline, beryl, spodumene, and rare-element minerals.
Field identification & locations
Identify it by visible centimeter-scale interlocking quartz and feldspar crystals, unlike uniform fine-grained granite; quartz lacks cleavage, while feldspar cleaves into blocky faces. Common worldwide in granitic terrains and pegmatite districts.
