mineral
Tumbled chalcedony or quartz-rich chert
Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide staining
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; pale cream, pink, and gray coloration with a waxy to dull luster and no visible cleavage. The rounded shape suggests natural water wear or tumbling; translucency at the edges is typical of chalcedony.
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Physical properties
Hardness about 6.5–7 Mohs; pale cream, pink, and gray coloration with a waxy to dull luster and no visible cleavage. The rounded shape suggests natural water wear or tumbling; translucency at the edges is typical of chalcedony.
Formation & geological history
Forms when silica-rich groundwater fills cavities or replaces material in volcanic and sedimentary rocks; iron oxides create the pink-orange patches. Precise geological age and locality cannot be determined from the photograph.
Uses & applications
Used for beads, cabochons, carvings, ornamental stone, and lapidary practice; attractive polished pieces have modest jewelry value.
Geological facts
Chalcedony is a microcrystalline variety of quartz whose crystals are too small to see individually; related varieties include agate, jasper, and carnelian.
Field identification & locations
Check for glassy/waxy luster, translucency, conchoidal fracture, and resistance to scratching by a steel knife; quartz will scratch ordinary glass. Common in volcanic terrains, gravel deposits, and silica-rich geodes.
