The precious opals
Jewelry and gemstone lovers choose to buy a precious opal mainly because of its shimmering colors. There are several theories about where the opal got its name from. The most likely one refers to the Roman term “opalus”, which means “valuable stone”. Among opals, precious opals are particularly valuable and popular.
Opalescence: the play of colors of precious opals
Noble opals have a property that makes them unique among all gemstones: they opalize. This means that although they have a “background color” (called the base color or body color), many iridescent colors can appear in the “foreground” and create a play of colors.
Noble opal consists of a regular arrangement of tiny silica spheres. These spheres refract light. The subsequent interference creates the play of colors. Opalescent opals can have a white, colorless or very dark gray or blue-black base color.
The group of precious opals
The precious opal refers to a group of opals. This group includes:
These are distinguished from Fire Opal and common opal. Fire Opal is a popular orange-red variety from Mexico. Common opals are widespread. They come in many different colors, but do not display any color play.
Origin: Most precious opals come from Australia.
Australia is the most important exporter of opals – 95 percent of the precious opals traded worldwide are mined there. About four percent come from Mexico and one percent from other parts of the world. In total, there are now over 4,000 sites where opals have been found.
The conditions in Australia are ideal for the formation of opals. The seasonal rains soak the parched outback. Silica deposits are thus transported underground into cracks between the rock layers. When the water evaporates, these deposits become opal. Opalized fossils are formed when the opals form around wood, shells and skeletons.
Use: Ideal for unique jewelry
Precious opals are mainly used for jewelry. Each stone shows an individual and therefore unique play of colors. This results in equally unique and individual pieces of jewelry.
If you buy a precious opal in the IGNEOUS gemstone shop, you can have it made into rings, earrings or necklaces. Depending on the base color and personal preference, settings in silver, white, red or yellow gold are suitable.
If you are looking for a suitable birthday present for someone born in October, you should consider the opal. According to the American Gem Society, it is the birthstone of October. These beautiful stones can be given as gifts all year round as valuable lucky charms.
The properties of the precious opal
Opals have a hardness of 5.5 to 6 on the ten-point hardness scale according to Carl Friedrich Mohs. In addition, opals have a relatively high water content of about four to ten percent, in exceptional cases even up to 20 percent.
Most common cuts
The colors and opalescence are best shown off by smooth cuts such as the cabochon. They are usually cut into oval, triangular, drop-shaped or round forms. Free forms also occur.
While other gemstones usually look better on light-colored materials, the beauty of precious opals is best emphasized on a dark background. Therefore, a dark second layer is occasionally glued under the opal, which is hidden by the setting in jewelry and is therefore no longer visible. This is called a doublette. If a third layer is added, it is called a triplet.