mineral

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Tans, oranges, and yellows due to iron oxide staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Tans, oranges, and yellows due to iron oxide staining
Luster: Vitreous to greasy

Identified July 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins or as a primary constituent of igneous and metamorphic rocks. The yellowish coloring is a secondary surface stain or inclusion of iron minerals like limonite or goethite.

Uses & applications

Used in construction as a component of sand and gravel, in glassmaking, as an abrasive, and small tumbled pieces are popular in the metaphysical and jewelry markets.

Geological facts

Quartz is the second most abundant mineral in the Earth's continental crust. Specimens like this one are often mistaken for citrine, but citrine's color is within the crystal lattice rather than just on the surface.

Field identification & locations

Identified in the field by its hardness (it will scratch glass) and lack of cleavage. Common in riverbeds and mountainous terrain worldwide. Look for a waxy or glassy luster on fresh breaks.