The crystal system of Opal is amorphous, which means no crystal structure. The word opal is originated from Latin "opalus" from Greek "opallios", from Sanskrit "upala", which means "precious stones". These stones fall into the category of mineraloid.
These stones are known as the national gemstone of Australia and are almost found in every color. The hardness of opal on the Mohs scale is 5.5 to 6.5.
Mostly, Opal they are found in sedimentary rocks. The formation of opal can take a large amount of time. The Solution of silicon dioxide and water helps to form an opal. The heavy rainfall or runny water carries down silica from sandstone into the crack of rocks. After the water evaporates, the only thing that remains is silica gel which is believed to harden after a million years forming opal.
Almost 95% of the world's precious gemstone opal is produced in Australia, making them the largest producer in the world. The rest of the places where these stones can be found are Ethiopia, USA, Hungary, Brazil, Czech Republic, Mexico, Germany, and Indonesia. Hungary was one of the major producers of these stones and during ancient times, they mined these stones for Australia.
Louis Leakey, an anthropologist discovered Opal antiques in a cave in Kenya. These stones are believed to be originated from Ethiopia around 4000 BC. The first opal market was organized by the ancient Romans. As it was a rich and powerful kingdom, the wealthy citizens were very fond of gems like this. In the late 18th and early 19th centuries, opal was believed to bring bad luck and both the supply and demand started falling.
Opals are believed to be a gift from God. One of the myths that come from Ancient Greek is that tears started falling out the eyes of Zeus, the God of lightning after winning the battle against Titans. The tears started falling in the earth and after it fell on the ground, Opals formed. There are also many myths like Treasures from Cupid, Goddess of Rainbows and Rainbow Serpent.
Opal is related to love, honesty, creativity, and strength. These stones increase our will to live and reduce suicidal thoughts, strengthens our body physically and mentally, give us the courage to overcome fear and increases our creativity. When in anger, it helps us to calm down. It intoxicates the blood, cures fever and common colds, relaxes the depressed mind and fills our mind with positive thoughts and vibes.
The Opals that are found on Mars are known as Martian opal. One of the scientists, Martin Lee and his team discovered that these stones can be found in Mars while investigating the Nakhla Meteorite. Over a century ago, in 1911, it fell from Mars to Egypt. This lead the researchers to believe that once there was life on Mars.
Black opal is one of the rarest gemstones ever discovered. Of all opals, it is the most valued and sought after gems because of its color and rarity. The largest producer of black opal is Lightning Ridge which is a town in New South Wales, Australia. Its price can vary from $300 to $3000 by its quality.
Olympic Australis is the largest and most famous of all opals ever found. In 1956, Bert Wilson and his team discovered it at the "eight-mile" mining field of Coober Pedy, Australia. Its name was given in the honor of the Olympic games that was going to take place in the same year.
It is 280 mm long, 120 mm thick, 115 mm wide and weighs 17,000 carats. It was worth $2.5 million. The Altmann & Cherny bought it and thoroughly polished ad cut it in oval shape. Today, we can find it in the Altmann & Cherny showroom of Sydney, Australia.
The Aurora Australis is the most valuable black opal to be ever found. It was discovered in 1938 at Lightning Ridge of New South Wales, Australia. The name was given by its color that represents the bright southern light. It measures 3 inches by 1.8 inches and weighs 180 carats. This opal is rare because of its strong vibrant color play and its size. It's estimated value is $1 million.
Opals can be cut almost in every kind of shape and size. Some most common shapes are oval, square, circular, round, rectangle, triangle and marquise. Just like other gemstones, sizes of opal can vary from big to small. Of all these stones, white opal is the most common and black opal is rarest of them all. Other colors are grey, green, yellow, red, and orange.
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