mineral
Rounded iron-rich river pebble
Likely limonite/goethite-bearing rock; exact identification requires testing
AI-generated identification · may be incorrectDark brown, earthy to submetallic luster, fine-grained and smoothly water-worn; estimated hardness about 4–6 Mohs, with no visible cleavage or crystals. It may be weakly to strongly magnetic if magnetite is present, and typically has moderate-to-high specific gravity.
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Physical properties
Dark brown, earthy to submetallic luster, fine-grained and smoothly water-worn; estimated hardness about 4–6 Mohs, with no visible cleavage or crystals. It may be weakly to strongly magnetic if magnetite is present, and typically has moderate-to-high specific gravity.
Formation & geological history
Likely formed by weathering and concentration of iron oxides, then rounded by stream or shoreline abrasion; the source rock and age cannot be determined from the photograph. Commonly occurs in alluvial gravels and weathered iron-rich terrains.
Uses & applications
Usually a landscaping, craft, or curiosity specimen; iron-rich material may be used as a minor ore, pigment, or polishing stone, but this piece has no apparent gem value.
Geological facts
A reddish-brown streak on unglazed ceramic would support hematite or limonite, while a black streak and strong magnetism would suggest magnetite. Surface color alone cannot distinguish these minerals reliably.
Field identification & locations
Look for unusually high density, rusty streaks, earthy texture, and magnetic response; common in streambeds worldwide, especially regions with basalt or ironstone. Estimated value: $1–$10 as a common pebble, or up to roughly $20 if unusually magnetic or locally significant.
