igneous

Granitic Pegmatite (with Pink Feldspar and Quartz)

Pegmatite (KAlSi3O8 + SiO2)

Hardness: 6-7 (Mohs scale), Color: Pink, white, and smoky grey, Luster: Vitreous to pearly, Crystal Structure: Monoclinic (feldspar) and Hexagonal (quartz), Cleavage: Perfect in two directions for feldspar; none for quartz, Specific Gravity: 2.55-2.75

Identified May 23, 2026More igneous →

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Physical properties

Formation & geological history

Formed during the final stages of magma crystallization where high water content allows for the growth of very large crystals. Typically found in intrusive igneous bodies or dikes, often billions to hundreds of millions of years old.

Uses & applications

Pink feldspar is used in glass and ceramic manufacturing, while quartz is used in electronics and glass. Pegmatites are also primary sources for gemstones and rare-earth elements.

Geological facts

Pegmatites are famous for containing the largest crystals ever found on Earth; a single specimen of spodumene found in a pegmatite measured over 40 feet long. They often contain rare minerals like tourmaline, beryl, and topaz.

Field identification & locations

Identify in the field by looking for extremely coarse-grained texture (crystals > 1cm) and the presence of interlocking pink potassium feldspar and glassy quartz. It is commonly found in mountainous regions with exposed granitic basements.

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

mineral

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

mineral

Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral