Gem Library

BUYER’S OVERVIEW:
Chalcedony is a catch-all term for a type of quartz that contains microscopically small crystals (cryptocrystalline). Chalcedony also refers more specifically to semi-transparent or translucent Chalcedony with a solid color (commonly pale bluish-gray) and near wax like luster. The Chalcedony family includes such gemstones and minerals as; chrysoprase, carnelian, chrysocolla, onyx, agate, jasper, bloodstone, aventurine, flint, chert, sard, sardonyx and even petrified wood!

While all varieties of Chalcedony are not abundant in nature, Chalcedony is not rare and good size stones are available. Chalcedony in its various forms is available in almost all naturally occurring colors.

COLOR:
Almost all naturally occurring colors.

APPEARANCE:
Semi-transparent to translucent or opaque, solid or patterned.

SIZE RANGE:
Large stones are common in many varieties of Chalcedony.

TYPICAL CUTTING STYLES:
Cabochons, cameos, intaglios, carvings, beads, and tablets.

POSSIBLE ENHANCEMENTS & TREATMENTS:
Chalcedony is typically dyed to create colors for various uses. This enhancement is generally stable. Chalcedony is often times heated to produce orange or orange / red stones from yellow to brown material. This enhancement is stable.

HARDNESS:
6½ to 7 on the Mohs scale.

BEST USE OF THE GEMSTONE:
Chalcedony can be used in all types of jewelry.

CARE & CLEANING:
It is best to never expose colored gemstones to cleaning solvents or chemicals of any kind.
Common cleaning methods include:
Ultrasonic: usually safe
Steamer: usually safe
Warm soapy water: safe
Reaction to Chemicals: can be damaged by acids and alkalis.
Reaction to Heat: heat may cause the stone to change color.
Stability to Light: most stones are stable following prolonged exposure to sunlight / UV light.

INTERESTING FACTS ABOUT THIS GEMSTONE:
The most common forms of Chalcedony are agate and jasper. Agate is usually translucent and has clearly defined bands and markings, while jasper is generally opaque, more irregular and less defined.

DESIGNATION:
None documented.

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