igneous

Granitic Quartz or Pegmatite

Quartz with Orthoclase Feldspar (SiO2 + KAlSi3O8)

Hardness: 6-7 on Mohs scale; Color: Smoky yellow-brown with salmon-pink inclusions; Luster: Vitreous to greasy; Crystal structure: Hexagonal (Quartz) and Monoclinic (Feldspar); Conchoidal fracture on quartz surfaces.

Hardness: 6-7 on Mohs scale
Color: Smoky yellow-brown with salmon-pink inclusions
Luster: Vitreous to greasy

Identified April 8, 2026More igneous →

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Physical properties

Formation & geological history

Formed from the slow cooling of magma deep within the Earth's crust, typical of intrusive igneous environments like batholiths or pegmatite veins where large minerals have time to solidify.

Uses & applications

Used in construction as crushed stone or landscaping gravel; high-quality quartz is used in electronics and glassmaking; feldspar is used in ceramics and glass.

Geological facts

This specimen shows a mix of quartz (the translucent, glassy parts) and feldspar (the opaque, pinkish-orange parts). This combination is the foundation of most Earth continental crust.

Field identification & locations

Identify in the field by looking for 'glassy' translucent surfaces that don't have parallel edges (quartz) mixed with opaque, blocky crystals that show flat cleavage faces (feldspar). Commonly found in mountainous regions or riverbeds downstream from granitic outcrops.

Other igneous specimens

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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