mineral

Tumbled blue stone with a drilled hole

Likely dyed or naturally blue chalcedony/agate; identity cannot be confirmed from the photo

AI-generated identification · may be incorrect

Blue-gray, finely granular, waxy to dull luster, with a central drilled hole and a small tan-brown exposed inclusion or filler. Chalcedony is quartz (SiO₂), hardness ~6.5–7, cryptocrystalline, with no visible cleavage and specific gravity ~2.6.

Identified August 12, 2026More mineral →

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Physical properties

Formation & geological history

If chalcedony, it formed when silica-rich groundwater filled cavities in volcanic rock, commonly during the Cenozoic or older volcanic episodes. The rounded shape is human-tumbled and drilled; blue color may be natural, dyed, or surface-treated.

Uses & applications

Used as a bead, pendant, craft stone, or decorative specimen; chalcedony and agate are also used in carvings and jewelry. Common quality is inexpensive.

Geological facts

Blue dyed agate and “blue quartz” are frequently sold as beads, making visual identification alone unreliable. A white or gray interior beneath scratches would suggest dye treatment.

Field identification & locations

Common sources include Brazil, Uruguay, India, Madagascar, Mexico, and the western United States. Check translucency, hardness, dye concentration around the hole, and test with a loupe; avoid destructive tests on finished pieces.