Chalcedony is a mixture of cryptocrystalline quartz and another silicon mineral called moganite. Chalcedony is usually divided into translucent varieties such as (blue) chalcedony, carnelian, chrysoprase, or banded varieties under the name agate, as well as opaque varieties known as jasper.

Physical properties:

Optical properties:

Grinding wheel:

All grit sizes

Facet polishing:

Usually not faceted, but if so, it is polished like regular crystalline quartz

Cabochon polishing:

Orientation:

According to shape and color

Treatments/synthetics:

Due to its fibrous or granular structure, chalcedony can be easily dyed.

Tips!

LightningLap with cerium oxide is excellent for polishing large facets.

Kalcedon on Gemdat