mineral
Iron-Stained Quartz (Red Quartz)
Silicon Dioxide (SiO2) with Hematite/Limonite inclusions
Hardness 7 on the Mohs scale, reddish-brown to orange-tan exterior coating, vitreous to greasy luster, trigonal/hexagonal crystal system, indistinct/no cleavage, glassy conchoidal fracture.
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Physical properties
Hardness 7 on the Mohs scale, reddish-brown to orange-tan exterior coating, vitreous to greasy luster, trigonal/hexagonal crystal system, indistinct/no cleavage, glassy conchoidal fracture.
Formation & geological history
Forms in hydrothermal veins or pegmatites where silica-rich fluids crystallize. The red/brown coloration is due to iron oxide (hematite or limonite) staining on the surface or coating internal fractures.
Uses & applications
Popular as mineral specimens, lapidary material, decorative display stones, and tumbled rocks.
Geological facts
When iron oxide is trapped inside the crystal structure during growth, it creates orange to red specimens often called 'Hematoid Quartz' or 'Ferruginous Quartz'.
Field identification & locations
Can be identified by its glassy interior, conchoidal fracture, and ability to scratch glass (Mohs 7). Commonly found in quartz veins and gravel deposits worldwide, particularly in Brazil, Madagascar, and parts of North America.
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