mineral
Polished agate/jasper pebble (probable)
Microcrystalline quartz, SiO₂, with iron-oxide and other inclusions
AI-generated identification · may be incorrectGray, cream, brown, and yellow material with a waxy-to-glassy luster and irregular banding; quartz hardness is about 6.5–7 Mohs, with no obvious cleavage and conchoidal fracture. The rounded shape and reflective surface indicate natural abrasion and/or polishing.
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Physical properties
Gray, cream, brown, and yellow material with a waxy-to-glassy luster and irregular banding; quartz hardness is about 6.5–7 Mohs, with no obvious cleavage and conchoidal fracture. The rounded shape and reflective surface indicate natural abrasion and/or polishing.
Formation & geological history
Likely formed when silica-rich groundwater filled cavities in volcanic rock, later developing chalcedony bands and iron staining; the exact geological age cannot be determined from the image. Common sources include Brazil, Uruguay, India, Madagascar, Mexico, and the western United States.
Uses & applications
Used for lapidary cabochons, beads, carvings, ornaments, and occasionally decorative stone; this piece appears suitable as a small cabochon or display pebble.
Geological facts
Agate is a variety of chalcedony, composed of cryptocrystalline quartz rather than large visible crystals. The yellow coloration commonly comes from limonite or other iron minerals.
Field identification & locations
Identify it by its fine-grained, translucent-to-opaque body, curved banding, waxy polish, and resistance to scratching by steel; confirm quartz hardness with a careful scratch test. The image could also represent jasper or silicified material, so laboratory testing would be needed for certainty.
