mineral

Tumbled blue chalcedony (likely blue lace agate)

Microcrystalline quartz, SiO₂; chalcedony with possible agate banding

AI-generated identification · may be incorrect

Pale blue-gray, translucent to opaque, waxy-to-glassy luster, and no obvious cleavage; Mohs hardness 6.5–7, specific gravity about 2.6. The lower piece shows curved translucent bands and dark matrix/inclusions, consistent with chalcedony or agate.

Identified September 1, 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

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, depositing cryptocrystalline quartz in layers. Blue lace agate commonly formed in volcanic rocks, especially in Precambrian settings; the exact age and variety cannot be confirmed visually.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and inexpensive display specimens. Typical value is modest unless color, translucency, and banding are unusually strong.

Geological facts

“Blue lace agate” is a trade name for finely banded blue chalcedony, while plain blue chalcedony may lack visible bands. Some commercial blue material is dyed, though these pieces appear naturally muted.

Field identification & locations

Likely identification requires close inspection: chalcedony feels smooth and waxy, is hard enough to scratch glass, and does not react with dilute acid. Around 49.0°N, 122.3°W, glacial gravels can contain transported quartz and agate from British Columbia and the North Cascades, but locality cannot be established from the photo.