mineral

Chalcedony (Blue/Grey Lace Agate)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Pale blue, lavender, or grey with subtle banding. Luster: Waxy to vitreous. Crystal Structure: Trigonal (cryptocrystalline). Cleavage: None. Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Pale blue, lavender, or grey with subtle banding
Luster: Waxy to vitreous

Identified April 28, 2026More mineral →

Explore Chalcedony (Blue/Grey 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

Formed from the deposition of silica-rich water in cavities (vugs) within volcanic and sedimentary rocks. Typically formed during Cenozoic eras in secondary hydrothermal environments.

Uses & applications

Commonly used in jewelry for cabochons and beads, as well as for decorative carvings, orbital polishers, and spiritual or metaphysical collecting.

Geological facts

Chalcedony is a cryptocrystalline form of silica, meaning its crystals are so small they can only be seen with extreme magnification. It has been used since the Bronze Age for seals and cylinder stamps.

Field identification & locations

Identify by its waxy luster, lack of cleavage, and translucent edges. It is often found in riverbeds or volcanic outcrops. Major deposits are found in Namibia, Brazil, and the USA (South Dakota and Oregon).