mineral

Iron-stained quartz crystal

Quartz (SiO₂), likely iron-oxide-coated or included

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent rusty orange-brown color, vitreous luster, and irregular crystal faces/fracture. Quartz is trigonal and lacks cleavage; the reddish coloration likely comes from hematite or limonite coatings/inclusions.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich hydrothermal fluids or groundwater deposited quartz in a cavity, vein, or fracture; iron oxides later stained the crystal. The specimen’s precise geological age and locality cannot be determined from the image.

Uses & applications

Used primarily as a collector specimen; quartz is also important in glassmaking, electronics, abrasives, and engineered stone. This rough, iron-stained piece has limited jewelry value unless cut or polished.

Geological facts

The apparent reddish-brown material may be hematite (Fe₂O₃) or limonite rather than intrinsic quartz color. A steel file should not scratch fresh quartz, while quartz can scratch ordinary glass.

Field identification & locations

Common in quartz veins, geodes, pegmatites, and hydrothermal deposits worldwide, especially Brazil, Madagascar, the United States, and Mexico. Confirm with a hardness test, glassy luster, and lack of cleavage; acid testing is unnecessary.