igneous

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Hardness: 7 (Mohs scale for quartz); Color: White to grey with tan/brown matrix; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale for quartz)
Color: White to grey with tan/brown matrix
Luster: Vitreous to dull

Identified February 21, 2026More igneous →

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Physical properties

Formation & geological history

Formed through hydrothermal processes where mineral-rich hot water circulates through fractures in existing rock, depositing silica as it cools. Most commonly found in orogenic belts and volcanic environments.

Uses & applications

Quartz is used in glassmaking, electronics (piezoelectric properties), and construction. This specific rough specimen is primarily of interest for geological study or amateur collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Vein quartz often acts as a 'trap' for precious metals like gold in hydrothermal systems.

Field identification & locations

Identify by trying to scratch glass (quartz will scratch it); look for the crystalline structure within the vugs or pockets. Common in mountain ranges and areas with past volcanic/tectonic activity.

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Fluorapatite (Ca5(PO4)3F)

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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)

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Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

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

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Magnetite

Magnetite (Fe3O4)

mineral