mineral
Likely iron-stained quartz/chalcedony fragment
Quartz (SiO₂), possibly brecciated or partly chalcedonic, with iron-oxide staining
AI-generated identification · may be incorrectBrown-red and gray translucent areas, vitreous to dull luster, irregular fracture, and no clearly visible cleavage; quartz hardness is Mohs 7 and specific gravity about 2.65. The image is somewhat limited, so crystal habit and exact texture are uncertain.
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Physical properties
Brown-red and gray translucent areas, vitreous to dull luster, irregular fracture, and no clearly visible cleavage; quartz hardness is Mohs 7 and specific gravity about 2.65. The image is somewhat limited, so crystal habit and exact texture are uncertain.
Formation & geological history
Likely formed when silica precipitated in a cavity, vein, or fracture and was later stained or cemented by hematite/goethite. Such material commonly formed during hydrothermal or groundwater alteration, with age dependent on its host geology.
Uses & applications
Used as a decorative or lapidary material when attractive; otherwise mainly a common collector specimen. It has little industrial value as an isolated fragment.
Geological facts
The red-brown coloration commonly comes from microscopic iron oxides rather than the quartz itself. It may also represent jaspery quartz, agate, or a small breccia fragment.
Field identification & locations
Test by scratching glass (quartz should scratch it), checking for a white streak, and examining translucency under strong light. Common in quartz veins, weathered iron-rich zones, and gravel deposits worldwide; acid testing is generally uninformative.
