igneous
Pegmatite with muscovite mica
Granitic pegmatite; quartz (SiO₂), feldspar, and muscovite (KAl₂(AlSi₃O₁₀)(OH)₂), locally biotite/tourmaline
AI-generated identification · may be incorrectCoarse-grained, white to pink, with glassy quartz, blocky feldspar, and shiny platy mica. Quartz hardness 7, feldspar 6–6.5, muscovite 2–2.5; nonmetallic luster, mica has perfect basal cleavage, and crystals are intergrown rather than uniformly structured.
Identified More igneous →
Explore Pegmatite with muscovite mica in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse-grained, white to pink, with glassy quartz, blocky feldspar, and shiny platy mica. Quartz hardness 7, feldspar 6–6.5, muscovite 2–2.5; nonmetallic luster, mica has perfect basal cleavage, and crystals are intergrown rather than uniformly structured.
Formation & geological history
Forms from the final, volatile-rich fluids of slowly cooling felsic magma, producing exceptionally large crystals in veins and pockets. Most pegmatites are Precambrian to Mesozoic, depending on locality.
Uses & applications
Used as a source of feldspar, quartz, mica, lithium, beryllium, and rare elements; attractive pieces are sold as mineral specimens, though this sample is mainly a collector specimen.
Geological facts
The dark, reflective flakes are likely muscovite or biotite mica; white masses are quartz and feldspar. Pegmatites can host spectacular gemstones such as tourmaline, beryl, and spodumene.
Field identification & locations
Common in granitic terrains and exposed pegmatite dikes worldwide, especially Brazil, Madagascar, the United States, and Scandinavia. Identify it by very coarse interlocking crystals and mica sheets that split into elastic flakes.
