mineral

Tumbled dark stone, likely banded iron formation or hematite-rich jasper

Hematite-bearing quartz/jasper; probable iron oxide–silica aggregate

AI-generated identification · may be incorrect

Dark brown to black, opaque, with a smooth tumbled polish and faint reddish-brown streaking; likely Mohs 5.5–7, submetallic to earthy luster, no visible cleavage, and relatively high specific gravity if hematite-rich.

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed from silica-rich chemical sediments and iron oxides precipitated in ancient marine basins, commonly during the Precambrian (roughly 2.5–1.8 billion years ago), then silicified and compacted.

Uses & applications

Used as a lapidary stone, cabochon, or collector specimen; hematite-rich material is also an iron ore, while jasper is used decoratively.

Geological facts

The photograph alone cannot distinguish hematite jasper from other dark polished stones such as basalt, magnetite-rich rock, or slag. A red-brown streak on unglazed porcelain and strong attraction to a magnet would support hematite/magnetite content.

Field identification & locations

Common sources include Michigan and Minnesota, Brazil, Australia, India, and South Africa. Field identification requires streak, magnetism, density, and close inspection for quartz or jasper banding.