Fire Opal

On my last post a comment raised the question on how Opals differ from Chrysocolla. It inspired me for my next post – so here it is : Opals. Opals are actually a whole genre of gemstones that contains many varieties, so I will only focus on the Fire Opal in this post (all pictures in this post are of Fire Opals). But first of, some general comments on Opals.

Opal is amorphous SiO2·nH2O, hydrated silicon dioxide, the water content sometimes being as high as 20% but is usually between three and ten percent. Opal ranges from clear through white, gray, red, yellow, green, shore, blue, magenta, brown, and black. Of these hues, red and black are the most rare and dear, whereas white and green are the most common.

The word Opal comes from the Latin opalus, by Greek òpalliòs, by Sanskrit upálá[s] for “stone”, originally a millstone with upárá[s] for slab. The veins of opal displaying the play of color are often quite thin, and this has given rise to unusual methods of preparing the stone as a gem. An opal doublet is a thin layer of colorful material, backed by a black mineral, such as ironstone, basalt or obsidian. The darker backing emphasizes the play of color, and results in a more attractive display than a lighter potch. Given the texture of opals, they can be quite difficult to polish to a reasonable lustre.
“Numerous legends and tales surround this colourful gemstone, which can be traced back in its origins to a time long before our memory, to the ancient dream time of the Australian aborigines. It is reported in their legends that the creator came down to Earth on a rainbow, in order to bring the message of peace to all the humans. And at the very spot, where his foot touched the ground, the stones became alive and started sparkling in all the colours of the rainbow. That was the birth of the Opals.

The group of fine Opals includes quite a number of wonderful gemstones, which share one characteristic: they shine and sparkle in a continually changing play of colours full of fantasy, which experts describe as “opalising”. Depending on the kind, place of occurrence, and colour of the main body, we differentiate Dark or Black Opal, White or Light Opal, Milk or Crystal Opal, Boulder Opal, Opal Matrix, Yowah Nuts from Queensland – the so-called “picture stones“, and also Mexican and Fire Opal.

Australia is the classical Opal country and today is the worldwide most important supplier of Fine Opals. Almost 95 per cent of all Opals come from Australian mines. The remaining five per cent are mined in Mexico, and in Brazil’s north, also in the US states of Idaho and Nevada, but recently the stones have also been found in Ethiopia and in the West African country of Mali.“

“It is in Mexico that the most significant fire opal deposits in the world lie. Rock strata containing opals run through the Mexican highlands, with their many extinct volcanoes. With a few exceptions, the gemstone, which lies hidden in cavities and crevices, is extracted in open-cast mines, the work giving rise to impressive canyons with walls up to 60 metres high and labyrinthine passages which wind their way through the mining areas.

The Mayas and Aztecs loved this gemstone and liked to use it in mosaics and for ritualistic purposes. They called it quetzalitzlipyollitli, the ’stone of the bird of paradise’ “

Australia produces around 97% of the world’s opal. 90% is called ‘light opal’ or white and crystal opal. White makes up 60% but not all the opal fields produce white opal; Crystal opal or pure hydrated silica makes up 30%; 8% is black and only 2% is boulder opal.

Fire opal, or Girasol, is a translucent to semi-opaque stone that is generally yellow to bright orange and sometimes nearly red and displays pleochroism at certain angles.

Not all fire opals are the same. There are the common fire opals, which, depending on their quality, are either faceted or cut into cabochons, and the especially valuable ones, which, in addition to their vivacious colour, also have the gaudy play of colour typical of opals. But with or without play of colour, the fire opal plays its part as a top quality gemstone to perfection.

Fire opal is found mostly in Mexico and Mesoamerica. In South America, a city called Pedro II, located in Brazil, produces opal that was discovered in 1930.

“Fire opals are either faceted – that is, as far as their transparency allows – or cut as a cabochon, since this is the shape which best brings out the rich glow of this orange jewel. It is the oval which is regarded as the classical shape for valuable fire opals. Brazilian raw stones, however, are also cut into many other imaginative shapes, their sheer size giving cutters and gemstone designers almost unlimited freedom for both work and play.”

“The tolerance of the fire opal to extreme heat is just as poor as its resistance to acids, alkaline solutions and sharp objects. Very unfavourable conditions compel the opal to surrender its moisture, which can make it cloudy and cracked. Like all opals, it should not be exposed to intense light over long periods. However, it loves to be worn a lot, since this enables it to maintain its water balance, using the moisture of the wearer’s skin and that of the air. Having said that, it should be protected against contact with cosmetics. Fire opals which have become matt through being worn a great deal can be repolished.”

The drier the place where it is found, the more durable the Fire Opal will be.

Virgin Valley Fire Opals are the most spectacular speciman fire opals in the world. They emit vivid flashes of color – blue, green, gold, red, and peacock combinations. The crystal, ranging from clear to black, is formed as petrified wood.

Virgin Valley fire also occurs in a petrified wood cell structure called conk. This is a very rare form of fire opal. Because of the “matrix” this form is naturally stable. However, these pieces might be more valuable as rare fossil specimens because of their obvious wood grain and texture.

Virgin Valley is located in a remote Northwest section of Nevada, 29 miles west of Denio. It is in the middle of a national wildlife refuge.

The Opal is found in hard, heavy, clay layers. The clay layers consist of volcanic ash deposited between 12 and 20 million years ago.

Judy Hall’s Crystal Bible also refers to Opals as a group, general characteristics she mentions are :

• Delicate stone with fine vibration
• It enhances cosmic conciousness and induces psychic end mystical visions.
• Stimulates orginality and dynamic creativity
• Aids in accessing and expressing one’s true self
• Picks up thoughts and feelings, amplifies them, and retyurns them to the source
• A karmic stone, it teaches that what you put out comes back
• Emotionally it has always been associated with love and passion, desire and eroticism
• Opal strengthens the will to live
• Treats Parkinson’ disease, infections, fevers and strengthens memory.
• Purifying the blood and kidneys, it regulates insulin, eases childbirth and alleviates PMS (use dark colors)
• Place as appropriate, especially on the heart or solar plexus. Wear on little finger.

Fire Opal :

• Enhancer of personal power, awakening inner fire and a protector against danger
• Symbol of hope, excellent for business and an energy amplifier
• Facilitates change and progress
• For letting go of the past
• etc.

 

For more general Opal info : Wikipedia, Mindat and Web Mineral

For Fire Opal info : Gemstone , MindAt and Arizona Rock Shop

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