mineral

Tumbled pale-blue chalcedony (likely blue lace agate)

Microcrystalline quartz, SiO₂; chalcedony, possibly banded blue lace agate

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, vitreous to waxy luster, translucent blue-gray color, cryptocrystalline quartz structure, and no visible cleavage; specific gravity is about 2.60–2.65. The smooth rounded surface indicates tumbling or polishing.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, depositing microcrystalline quartz, often in volcanic rocks; blue lace agate is especially associated with Precambrian formations of Namibia. Exact age and identity require geological testing.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; polished pieces are also popular as desk or pocket stones.

Geological facts

Blue coloration commonly comes from trace minerals or microscopic inclusions rather than blue quartz itself. Chalcedony may fluoresce weakly under ultraviolet light, depending on impurities.

Field identification & locations

Identify by its smooth waxy appearance, translucency, hardness, and absence of cleavage; glass may look similar but is usually more uniformly clear and can show bubbles. Common sources include Namibia, Brazil, Uruguay, India, and Madagascar.