Class: Oxides and hydroxides.
Formula: SiO2 ♦ nH2O, hydrous silicon dioxide.
Hardness: 5.5-6.5.
Specific Gravity: 3.96.
Color: colorless, raznookrashenny.
Feature: white
Opal is often found as thin layers or flat lenses, large pieces are rare.
It occurs on all continents, but in Australia the field for about 97% of world production. 90% referred to as "light opal 'or white crystal opals. Most Australian opal is mined in Coober Pedy in South Australia. Type of Boulder mined in Queensland. One of the largest mines producing this type is Janda (born Jundah). In New South Wales, and procuring another opal with predominant black coloring (with the play of colors from dark gray to black and blue). This type is considered the most rare, as the black opal has only about 5% of the total number killed in the Australian Opals.
Most precious opal is mined in Australia, Mexico, Brazil, Guatemala, Honduras, Japan, Czech Republic, USA (Nevada), minor manifestations in Russia (Kamchatka) and the Ukraine.
Ordinary and fire opals are often found in Mexico (the states of Hidalgo (state) and Queretaro), Brazil, Guatemala, Honduras, United States, Turkey and Kazakhstan.
In late 2008, NASA announced that it has found opals on Mars.
Varieties of opal
And today, many fans of precious stones will say that the opal - the most beautiful gems of nature.
Australian scientist Frank Leehman counted 134 varieties of opal. The name "precious opal" opal jewelry is used to having a play of colors.
Black Opal - the most expensive type of opal that is determined by its rarity and exceptional beauty of the game iriziruyuschih colors on a dark gray or black background. Black opals are also dark blue, dark green and dark brown with intense play of colors.
Fire Opal - Hyacinth, red, amber, honey-yellow.
Dzhirazol - bluish-white with a yellow-gold and reddish glow of the pale milky background.
Hyalite - colorless, like glass.
Gidrofan - "water" Opal, "eye of the world" - milky white, cloudy and dry completely transparent in water.
Opal ordinary - milk, wax, opaque to poluprosvechivayuschego.
Prazopal or Azul-opal - opal green.
Resin opal - matte black with a resinous luster.
Cacholong - blue-white porcelain, porous and stick to the tongue ignoble opal, is highly regarded in the East.
An example of opal - Si O2 with a variable water content. The amount of water varies from 5-10% and above and to determine the crystallization temperature of the parent rock during the formation of opal.
Opal never forms crystals. In nature it occurs in the form of nodular formations of stalactites, nodules, segregations of irregular shape. Opal is often develops in wood, shells, bones.
Look beautiful, "opal matrix" - blotches of precious opal in tellnuyu breed.
The nature of the game's unique color of opal is not fully elucidated Opal is a crypto-crystalline material - a solid hydrogel silica. It has been suggested that the reason the game - opalescence - may be the presence of opal water and air bubbles that have appeared in more hydrated soft opalescent gel transition to the stage of fossilization. This concerns first of all precious opal, which contains many sites with ordered domains. These areas reflect light of different wavelengths, hence the effect irisation inside the stone. Each package is reflective of its wavelength and provides the color and intensity, depending on the angle of observation.
Products
For noble opals a rule of thumb: if the play of colors is clearly visible from a distance of 60-90 cm in normal light, the opal has excellent quality.
If, however, and in good light to peer into the model to see the play of colors, this stuff is worth nothing, and no art treatment did not make it into a good jewelry stone.
A few words about the value of opal. Given its uniqueness among other gems and uniqueness of each stone individually, experts believe that in the case of opal his estimate - is often more fantasy than reality. What do you mean? In the textbook "Commercial gemology" G. Tsvetkov is an example.
Several years ago a leading American jewelry magazine conducted an unusual experiment. Ring with opal was presented to the assessment by one of several reputable jewelry companies. Minimum score of opal was $ 200, maximum - $ 5,500. That is the difference in assessment was 27.5 times!
There is nothing surprising in this. As is known, the estimate of jewels based on the principle 4C: color, clarity, handling, mass. And what are the evaluation criteria can be used for the manifestation of the phenomena of stones, in particular opalescence? Here, all define addiction of a living person - an expert. This is especially true collectible stones, including any precious opal can be called unique.
Medicinal properties
Ancient times opal and water, to insist on this mineral, used for the treatment of diseases such as various kinds of infections, heart disease. Litoterapevty suggest that this mineral treat nervous diseases, removes from the state of depression, relieves insomnia and nightmares, removes effects of stressful situations. It is believed that one should wear a stone that for prevention of colds. Some people believe that if you stare at Opal for several minutes a day, you can greatly improve vision and reduce eye pressure. In some countries, women are recommended to wear opal with infertility.
The effect on the chakras depends on the color of the mineral.
Talismans and Amulets
Opal is the mascot of talented people and practicing magicians. Gold ring with white opal - a talisman of health workers, giving them the ability to alleviate the suffering of others. Gold ring with black opal - a talisman of magicians, conferring the strongest of them prescient.
Compliance with the sign of the Zodiac:
Through the foggy luster and high water content Opals are stones correspond to the moon and the zodiac sign of Pisces in the circle. |
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