mineral
Tumbled dark pebble, likely hematite or magnetite
Hematite (Fe₂O₃) or magnetite (Fe₃O₄); identification is uncertain from the image alone
AI-generated identification · may be incorrectSmall rounded, polished black-gray specimen with metallic to submetallic luster. Hematite hardness 5–6.5, specific gravity ~5.3; magnetite hardness 5.5–6.5, specific gravity ~5.2 and is strongly magnetic.
Identified More mineral →
Explore Tumbled dark pebble, likely hematite or magnetite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Small rounded, polished black-gray specimen with metallic to submetallic luster. Hematite hardness 5–6.5, specific gravity ~5.3; magnetite hardness 5.5–6.5, specific gravity ~5.2 and is strongly magnetic.
Formation & geological history
Iron oxides form in igneous, metamorphic, and hydrothermal environments, or as weathering/concentration deposits; their ages range from recent sediments to Precambrian formations. Tumbling has smoothed the natural fragment.
Uses & applications
Used as an iron ore, pigment, polishing abrasive, and collectible; hematite cabochons are used in inexpensive jewelry. Magnetite is also used in dense media and industrial applications.
Geological facts
A magnet strongly attracting it favors magnetite; a red-brown streak favors hematite, while magnetite produces a black streak. The photo cannot reliably distinguish either mineral from other dark polished stones.
Field identification & locations
Common sources include banded iron formations, volcanic rocks, hydrothermal veins, and placer gravels worldwide. Test streak on unglazed porcelain, magnetism, and density; avoid scratching valuable surfaces.
