Blue opals
Blue Opal is a form of silica similar to quartz, but contains water in its mineral structure. Precious opal is composed of small spheres of silica arranged in regular patterns. The color of precious stones is caused by the diffraction of white light that penetrates practically all the colors of the rainbow. This play of colors depends on the angle of the light and can change as the gem is rotated. The size and placement of the spheres also controls the color range of this rare gem.
Where do they come from?
More than 95% of the world's supply is located in Australia. The main source is the town of Coober Pedy in South Australia. Another Australian city, Lightning Ridge in New South Wales, is where the most black opals are found. It gets its name from the mostly dark background they have. This darkness enhances the brilliant play of colors in the stone.
Whether an opal is "black" or not can be determined by ignoring all colors and focusing only on the overall body tone (blackness level of the background) of the opal.
Boulder opal engagement rings get its name from the fact that an iron substrate is part of its natural formation. Colors can also be extremely bright and vivid. Gem quality 'boulder opal' can be very expensive and can compete in price with some of the black varieties.
Another type of this gemstone is fire opals. They tend to be transparent and have a warm body color ranging from yellow to orange. They do not have the 'play of colour' associated with other types of opal and look completely different. The most famous source of fire opals is Mexico. Therefore, these opals are popularly known as "Mexican fire opals".
In 1974, a Frenchman named Pierre Gilson discovered a way to create beautiful blue opals with all the properties of natural opal except for the presence of water. The process takes over 12 months. The advantage of the Gilson variety is that it does not tend to crack as natural opal can when it loses water due to extreme temperature changes. The Japanese also "grown" the most beautiful fiery blue opals using a form of quartz, silica and zirconia. They are initially created in much the same way as Gilson's, but are then impregnated with a polymer as a stabilizer to ensure that the silica structure is completely bonded together and the vibrant play of colors is permanent. This crafted opal gemstone has fiery blue colors and flashes of turquoise that are truly breathtaking!
How do you value opals?
The most important factor affecting the price of an opal is the "play of colors", the colors themselves and the color pattern. Flashes of red will increase the value as it means most of the other colors will be visible. The thickness of the stone, the attractiveness of the color pattern, the cut, the weight and the finish are taken into account when grading opals. All of the following factors should be considered:
Play of colors in opal.
The brightness of the stone.
Gemstone body tone.
Color saturation and intensity..
Whether the opal appears dull when viewed from different angles.
Whether it is flat on top or has a rounded dome.
Size and weight.
Cut and shape.
How should I care for my opal jewelry?
Avoid extreme temperature changes that could cause the opals in your jewelry to crack.
Avoid knocking or scratching opal jewelry. Remove jewelry when playing sports or in the garden. Never wear your jewelry while doing household chores such as washing dishes or using chemicals or cleaning products.
Clean Opal Bracelet with a mild detergent in warm water using a soft cloth or brush. After cleaning, your opal jewelry should be rinsed in clean water to remove any residue.
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