mineral

Tumbled blue chalcedony (likely blue lace agate)

Microcrystalline quartz, SiO₂; blue lace agate is banded chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; pale blue with white/gray curved banding, waxy to vitreous luster, cryptocrystalline structure, and no cleavage. The rounded, polished shape indicates tumbling.

Identified August 20, 2026More mineral →

Explore Tumbled blue chalcedony (likely blue lace agate) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness 6.5–7 Mohs; pale blue with white/gray curved banding, waxy to vitreous luster, cryptocrystalline structure, and no cleavage. The rounded, polished shape indicates tumbling.

Formation & geological history

Silica-rich groundwater deposited microscopic quartz in cavities and fractures, commonly in volcanic rock; many blue lace agates formed during the Phanerozoic, especially in southern Africa. Exact identification and age require testing and locality information.

Uses & applications

Used as a lapidary stone for cabochons, beads, carvings, and inexpensive jewelry; polished specimens are popular with collectors.

Geological facts

Blue lace agate is prized for delicate blue-and-white lace-like bands, though similarly colored dyed chalcedony is common. Color may fade with prolonged sunlight or heat.

Field identification & locations

Look for translucent edges, waxy polish, curved banding, and quartz-like hardness; it should scratch glass but not be scratched by a steel knife. Common sources include Namibia, South Africa, Brazil, and Mexico.