mineral

Dyed and polished agate pebble

Microcrystalline quartz (SiO₂), likely chalcedony/agate with blue dye

AI-generated identification · may be incorrect

Tumbled, smooth, opaque cream-brown chalcedony containing dark blue dyed bands or surface-filled areas. Quartz hardness is about 6.5–7 Mohs, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage; the blue color appears artificial.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Agate forms when silica-rich groundwater fills cavities in volcanic rock, commonly during the Paleogene to recent geologic eras. This specimen has been cut or shaped, polished, and likely artificially dyed after formation.

Uses & applications

Used as a decorative stone, lapidary material, paperweight, or low-cost jewelry component; it has little industrial significance in this form.

Geological facts

Agate commonly shows concentric banding, but vivid uniform blue is a strong indicator of dye treatment. Dye may concentrate along pores, fractures, or natural band boundaries.

Field identification & locations

Look for waxy luster, very fine texture, conchoidal fracture, and hardness sufficient to scratch glass; natural blue agate is uncommon. Common sources include Brazil, Uruguay, India, Madagascar, and Mexico.