Tuesday, November 15, 2011

Gemstone Series--- Cameo

Cameo (Agate)

Birthstone Month:
Agate is associated with the birthstone month of May.
Agate is associated with the zodiac sign Gemini.
Chemical Make-up:
Agate is a Silicon Dioxide and is a variety of Chalcedony, which is a member of the Quartz family. It is scientifically classified as either a cryptocystalline or a microcrystalline Quartz.
History & Lore:
The name Agate is believed to derive from the Greek word given to a stone that was found thousands of years ago in the Achates River in South-western Sicily, now known as Dirillo River.
The word cameo is used to describe a method of carving, whereby a jewelry item features a raised image of one color and a background of another. With other gemstones, carving a cameo often involves a carved image (often a head portrait), made of one type of stone, set onto a different stone / material to create the cameo. With Cameo Agate however, it is possible to carve the entire cameo out of a single gemstone. This is due to the banding that occurs within some varieties of Agate.
Cameo engravings originating as far back as the 1st and 2nd centuries B.C. have been discovered and the cameo is believed to have been a popular jewelry adornment worn by well-to-do members of the Greco-Roman Empire.

Cameo jewelry has had a varied past and has often fallen in and out of favor. After the fall of the Roman empire Cameo jewelry did not see any real renaissance until the 17th and 18th centuries, with important developments taking place in the 19th century when an exceptionally high quality deposit was discovered and mined in southern Germany. This region quickly became the world's leading location for the production of Cameo and the techniques developed at this time have changed little since.
Agate has commonly been used to cure insomnia and to bring about pleasant dreams. It is also said to enhance the wearer's courage, improve perception and concentration, and to provide protection from dangers. Agate is believed to enhance trust and honesty, and to assist with acceptance to circumstances and emotions. In addition to this, Agate is believed to be able to improve memory, to bring protection from all dangers, and to be able to bring about victory and strength.
Agate in general is a widely distributed gemstone but is not currently in high demand. Cameo (Agate) however, is somewhat rare as less then two percent of all mined Agate is of high enough quality to be used for detailed cameos. This is because the Agate gemstones used need to exhibit even and parallel levels of color. The top layer needs to be lighter than the layer below.
It is documented that Agate was originally mined in any significant quantity in the Nahe River Valley in Germany in 1497. These findings gave rise to the cutting center of Idar-Oberstein, Germany. When the deposits of Agate began to dry up in the Nahe River Valley in the nineteenth century, deposits were found in Brazil which sparked the discovery of the country's wide and varied gemstone deposits. There are also known sources of Agate in Australia, China, Congo, Egypt, Iceland, India, Italy, Madagascar, Mexico, Nepal, Russia, the United States, and Uruguay.
Agate is rated at 6.5 to 7 on Moh's Scale of Hardness.
Common Cuts:
The cut is a very crucial trait for the end look of Agate. The colors of this stone are found in strips, bands, or blended in clouds. The cutter must concentrate on these natural strips/bands well, cutting to assure that their beauty will be enhanced. Agate is often found in Cabochon cuts but can actually be cut into most of the common gemstone shapes/cuts.

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