Opal is a stone used in jewelery that is back in great fashion. Find out what are the characteristics of the opal and why it is a must among your jewels. Opal is also the stone of October ♦︎
It’s back: they have recently used the opal some big names such as Cartier, Chaumet, Chopard… It pays to know something more about this stone that is unique among the gems used in jewelery, and which has a ancient history: in fact, the word opal comes from the Sanskrit upala, which has become opallios in greek language and opalus in latin (with meaning of gemstone).
Characteristics. According to the gemologists, the opal is a mineral amorphous (from a chemical point of view is a hydrated silica). But it is also a stone with many different aspects: its color can range from transparent to milky white, but also green, red, yellow, brown, black, iridescent. It has pearlescent and transparency effects. And more: the opal is a stone, yet he contains water in an amount of up to 20%.
Where is it. The capital of opals is Australia, where is 97% of world production, particularly in the area of Lightning Ridge, where we extract the precious black opal. But you can found opals also in Mexico, Wales and even in Sardinia.
Classification. Besides taking very different colors, this stone is spread in a wide variety: there are the common opal, opal noble, black opal, opal water, the fire opal, opal coal was and ialite. Also it varies the transparency can go from transucido to completely opaque. Another classification is related to brilliance. The rating scale following categories: Weak, Not bright, bright, very bright, brilliant.
Colors. The opals have the distinction of being opalescent. Obviously. Word that means, in fact, a game of colors and iridescent light. These iridescent effects are caused to interference and diffraction of light passing through the particular arrangement of small silica spheres inside the stone. One of the finest is the opal red Mexico. Another very popular variety is the black opal, where the iridescent colors stand out against a background that ranges from black (the most prized) to dark gray. In contrast, less rare opals are white (white) or clear (light).
Value. The opals are one of the stones more difficult to classify and to assess. The best are those in which the whole is a gem homogeneous. In trade, in reality, they are also some who have only part iridescent, which is linked together with other minerals: they are classified as bouldering.
Care. If you have jewelry with an opal, you must be careful not to expose the stone near heat sources: the heating can cause dehydration and, consequently, the loss of the effect of opalescence. If you notice that your opal is not iridescent as a time, try to soak down the stone in the water.