metamorphic
Orbicular jasper (likely)
Silicified, iron-rich volcanic rock with orbicular structures; exact mineralogy cannot be confirmed from the image
AI-generated identification · may be incorrectOpaque, tan-brown fine-grained matrix with rounded yellow, cream, and reddish spots. Likely quartz/chalcedony with iron-oxide coloring; hardness about 6.5–7 Mohs, dull to waxy luster, no obvious cleavage. Crystal structure is mostly microcrystalline.
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Physical properties
Opaque, tan-brown fine-grained matrix with rounded yellow, cream, and reddish spots. Likely quartz/chalcedony with iron-oxide coloring; hardness about 6.5–7 Mohs, dull to waxy luster, no obvious cleavage. Crystal structure is mostly microcrystalline.
Formation & geological history
Orbicular patterns commonly develop as minerals grow in concentric layers within volcanic rock, later silicified; the specimen’s age and locality cannot be determined visually.
Uses & applications
Often cut and polished for cabochons, beads, and decorative specimens; typically collected rather than used industrially.
Geological facts
The rounded markings resemble orbicules, but weathering, inclusions, or other textures can look similar in a small photograph.
Field identification & locations
Look for naturally repeated concentric bands and a hard, silica-rich surface; a scratch test and close inspection of a fresh surface can help distinguish jasper from softer ironstone. Orbicular jasper is reported from several volcanic regions worldwide.
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