Chalcedony

Scottish Agate Brooch.jpg

Victorian Scottish Agate Brooch.

Chalcedony is cryptocrystalline quartz. It is semitransparent to opaque and, depending on it's color, chalcedony is further divided in several varieties.

History

All varieties of chalcedony were very popular in Victorian Jewelry. Moss agate, known for its green tree-like patterns was a particular favorite. Bloodstone was often used for cameos and intaglios for gentleman's jewelry. Carnelian, also popular for intaglios, is often found in beads from the Victorian Era. Banded stones like sardonyx and onyx were used extensively for cameos and some of the most interesting beads feature banded agate. The term "hardstone" used in reference to a cameo usually refers to some form of chalcedony.

Victorian Era Scottish jewelry features many and varied combinations of chalcedony cut en cabochon and faceted sent in silver and sometimes gold. Often the pieces are fitted together mosaic style. Scottish agate or pebble jewelry as it is sometimes called, became fashionable after Victoria bought Balmoral Castle in 1848.

Chalcedony Varities
Agate
Various Colors, Banded or Interwoven
Bloodstone
Dark Green with Red Spots
Carnelian
Orangish to Brownish Red
Chrysocolla
Light Blue or Blue-Green
Chrysoprase
Apple Green
Fire Agate
Brown with Multicolor Iridescence
Jasper
All Colors Except Black
Onyx
Black & White
Petrified Wood
Multicolored Silicified Wood
Prase
Dull Green
Sardonyx
Brownish Red & White
Sard
Brownish Red to Orange

Gemological Information

Gemological information for chalcedony
Color All colors
Crystal structure Trigonal (polycrystalline quartz)
Family Quartz
Refractive index ~1.54
Durability Very durable
Hardness 7
Treatments Dying
Country of origin World wide deposits
Chalcedony care
Ultrasonic cleaning Usually safe
Steam cleaning Usually safe
Warm soapy water Safe
Chemical attack Avoid
Light sensitivity Stable (unless dyed)