Rock Identifier
Tumbled jasper (likely yellow/orbicular jasper) (Microcrystalline quartz, SiO₂, with iron-oxide and other mineral inclusions) — mineral
mineral

Tumbled jasper (likely yellow/orbicular jasper)

Microcrystalline quartz, SiO₂, with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque mustard-yellow to orange-brown with dark green-black patches, earthy/waxy to faintly vitreous luster, and no visible cleavage. The rounded shape and smooth surface indicate mechanical tumbling and polishing.

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Physical properties

Hardness about 6.5–7 Mohs; opaque mustard-yellow to orange-brown with dark green-black patches, earthy/waxy to faintly vitreous luster, and no visible cleavage. The rounded shape and smooth surface indicate mechanical tumbling and polishing.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic ash, sediments, or weathered rock, with iron oxides producing yellow-orange colors. Its exact geological age and locality cannot be determined from the photograph.

Uses & applications

Used for cabochons, beads, carvings, ornamental objects, and lapidary collections; generally not used as a structural stone.

Geological facts

Jasper is a variety of opaque chalcedony or microcrystalline quartz, commonly classified as a gemstone rather than a distinct mineral species. Dark patches may reflect manganese or iron-bearing inclusions, but visual identification is not definitive.

Field identification & locations

Typical field clues are opacity, fine-grained texture, high scratch resistance, and iron-rich coloration; it should not be scratched with steel if preservation matters. Common sources include Madagascar, Brazil, India, Mexico, and the western United States.