metamorphic
Polished orbicular jasper (likely leopard-skin or ocean jasper)
Silica-rich microcrystalline quartz/chalcedony, chiefly SiO₂, with iron-oxide and dark mafic inclusions
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; opaque cream, tan, black, and brown; waxy to dull luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded shape and smooth surface indicate tumbling or polishing.
Identified More metamorphic →
Explore Polished orbicular jasper (likely leopard-skin or ocean jasper) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 6.5–7 Mohs; opaque cream, tan, black, and brown; waxy to dull luster; cryptocrystalline quartz with no visible cleavage and conchoidal fracture. The rounded shape and smooth surface indicate tumbling or polishing.
Formation & geological history
Jasper forms when silica-rich groundwater replaces or cements volcanic ash and other sediments, commonly with iron and manganese staining; orbicular varieties develop concentric or irregular inclusion patterns. Precise geological age and locality cannot be determined from the image.
Uses & applications
Used for cabochons, beads, carvings, polished specimens, and ornamental stone; not generally used as structural building stone. Common commercial pieces are valued mainly for pattern and polish.
Geological facts
The specimen’s bold black-and-cream pattern is consistent with orbicular jasper, though visually similar brecciated jasper or jasperized volcanic rock is possible without testing.
Field identification & locations
Commonly found in volcanic terrains, especially Madagascar, Oregon, Mexico, India, and Australia. Check for quartz-like hardness, lack of cleavage, opaque patterns, and a fine-grained texture; a streak test and locality information would improve identification.
More like this
