mineral

Quartz (Citrine or Smoky variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Pale yellow to light brownish-tan; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Pale yellow to light brownish-tan
Luster: Vitreous (glassy)

Identified June 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous environments like pegmatites or hydrothermal veins as silica-rich fluids cool. It can also be found as secondary crystals in sedimentary geodes. Quartz is found in almost all geological periods.

Uses & applications

Commonly used as a gemstone for jewelry, in electronics for its piezoelectric properties, and as a popular collector's mineral due to its durability.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Citrine is the yellow-to-orange variety of quartz and is often rare in nature; many commercial citrines are actually heat-treated amethyst.

Field identification & locations

Identify by its hardness (it will scratch glass), its conchoidal (shell-like) fracture, and lack of true cleavage. Commonly found in riverbeds, mountains, and desert environments worldwide.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral