mineral

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Translucent yellowish-brown to tan; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Translucent yellowish-brown to tan
Luster: Vitreous to greasy

Identified July 13, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Translucent yellowish-brown to tan; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in a wide variety of environments, most commonly in hydrothermal veins and pegmatites. The coloration here is likely due to secondary iron oxide staining or inclusions within the crystal lattice.

Uses & applications

Mainly a collector specimen in this form. High-purity quartz is used in glassmaking, electronics (piezoelectric properties), and as an abrasive. Polished versions are used in jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. When clear and yellow, it is called Citrine, but natural brown/yellow tinting like this is often referred to as 'ferruginous quartz' or 'smoky quartz' depending on the cause of color.

Field identification & locations

Identify in the field by its hardness (will scratch glass easily) and lack of cleavage. Look for the characteristic conchoidal fracture patterns on the edges. Found globally in almost all geological terrains.