mineral
Tumbled brown mineral/rock specimen
Indeterminate from image; likely brown jasper, chert, or iron-stained quartzite
AI-generated identification · may be incorrectOpaque brown to dark brown, smooth rounded surface, dull-to-waxy luster, and no visible crystals or cleavage. Likely hardness about 6–7 Mohs if jasper/chert/quartzite; specific gravity approximately 2.6–2.7.
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Physical properties
Opaque brown to dark brown, smooth rounded surface, dull-to-waxy luster, and no visible crystals or cleavage. Likely hardness about 6–7 Mohs if jasper/chert/quartzite; specific gravity approximately 2.6–2.7.
Formation & geological history
Probably a naturally weathered and/or tumbled siliceous pebble, formed from microcrystalline quartz or quartz-rich rock; age and exact formation environment cannot be determined visually.
Uses & applications
Used as a decorative pebble, lapidary material, worry stone, or inexpensive cabochon; not typically used structurally because of its small size.
Geological facts
The elongated shape and uniformly polished surface suggest human tumbling or prolonged water abrasion. Brown coloration commonly comes from iron oxides and hydroxides.
Field identification & locations
Test identification with a streak, hardness test, and strong light: jasper/chert generally scratches glass and leaves a white streak, while softer brown rocks may not. Commonly found in river gravels and sedimentary terrains.
