mineral

Quartz (Citrine or Iron-stained variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: yellowish-brown to amber; Luster: vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: none (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: yellowish-brown to amber
Luster: vitreous (glassy) to greasy

Identified May 24, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: yellowish-brown to amber; Luster: vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: none (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in hydrothermal veins or as a secondary mineral in volcanic cavities (geodes). The yellow tint is often caused by submicroscopic iron impurities or natural radiation within the earth.

Uses & applications

Used in jewelry (gemstone), electronics for its piezoelectric properties, glass manufacturing, and as a popular decorative specimen for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Most commercial citrine is actually heat-treated amethyst or smoky quartz, but natural yellow quartz found in the wild is often colored by iron oxides.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and glassy appearance on broken surfaces. Commonly found in riverbeds, mountain regions, and tailings from old mines.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic

Green Apatite on Albite

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

mineral