Showing posts with label Opal. Show all posts
Showing posts with label Opal. Show all posts
Countdown now start for Opal Festival
The annual Opal Festival is just five short weeks away and this year is going to be huge with the National Opal Symposium, International Opal Jewellery Design-Awards Competition, Opal Trade Shows, Opal Queen, Opal Miner of the Year plus loads more. The Opal Symposium starts on Monday July 25 and the Opal Festival stall trading will end on Sunday July 31.
To mark the-occasion the Opal and Gem Expo has launched a new website www.lightningridgeopalfestival.com.au to promote the activities associated with the festival.
Opal Grading System Will Restore Confidence
Brisbane: based gemstone company Opal Horizon has-launched a comprehensive quantifiable opal grading system as the first step in a global marketing-effort to restore confidence in the gemstone.
Opal Horizon managing director-David Horton-said his company enlisted the expertise of international opal authorities to formulate the grading system in the hope that it would make opal gradings and valuations more transparent and therefore help increase worldwide acceptance of opals in the jewellery-industry.
World Opal Mines
Opal fits into the category of amorphous mineraloids because, unlike the others mineral gems, its structure is not truly crystalline. It consists of water and hydrated silicon dioxide. The water as an ingredient usually presents around three to ten percent but it can be as high as twenty percent. Stones with such high water percentage are very fragile and prone to cracking and dehydration and therefore their value is very low. Precious opal gemstones contain 4-6% of water. Opal is a type of gel or semi-liquid material that is formed at comparatively low temperature. They can be found in the fissures or gaps of any type of rocks. Most commonly opal is found in the fissures of basalt, limonite, rhyolite and sandstone. Boulder opal occurs in ironstone.
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