metamorphic
Tumbled yellow jasper or iron-stained quartzite
Microcrystalline quartz (SiO₂), likely jasper/quartzite with iron-oxide staining
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; mustard-yellow, cream, brown, and gray mottling; opaque to slightly translucent edges; vitreous to waxy luster; massive, with no obvious cleavage and conchoidal-to-uneven fracture. The rounded shape indicates natural water wear or tumbling.
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Physical properties
Hardness about 6.5–7 Mohs; mustard-yellow, cream, brown, and gray mottling; opaque to slightly translucent edges; vitreous to waxy luster; massive, with no obvious cleavage and conchoidal-to-uneven fracture. The rounded shape indicates natural water wear or tumbling.
Formation & geological history
Formed from silica-rich rock later altered or cemented, with yellow and brown colors caused mainly by limonite/goethite and other iron oxides. Its exact geological age and locality cannot be determined from the photograph.
Uses & applications
Used as a lapidary stone for cabochons, carvings, beads, and decorative objects; attractive polished pieces are collected but are generally inexpensive.
Geological facts
Jasper is an opaque variety of microcrystalline quartz, while quartzite is metamorphosed sandstone; visual separation may require a thin section or chemical testing.
Field identification & locations
Commonly found as rounded stream cobbles or in silica-rich gravel and iron-bearing formations worldwide. A steel file should not easily scratch it; vinegar has little effect, unlike carbonate rocks.
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