8.41 ct Incomparable Oval Cabochon (20 x 14 mm) Ethiopian 360 Degree Flashing Black Opal Natural Gemstone. Heated Multi Color Orgin From Ethiopia. 100% Natural Genuine Mined from Earth Gemstone!! 19.90 x 14.47 x 5.38 mm. Mohs Hardness - 5.5-6.5 Found in - Australia, Austria, Honduras, Brazil, Mexico, Zimbabwe, Ethiopia and the USA.
History - Opal is a semi-transparent solidified mineral composed of silicon and water. Black Opal refers to the dark background color of the stone behind the play of color. The name is derived from the Latin opalus and Sanskrit upala meaning "precious stone".
The Greek term opallios translates "to see a change in color". The oldest known opal mine is in Czechoslovakia and dates to 14th century.
Popularity of opal suffered in 19th century partially due to Sir Walter Scott's novel of a cursed stone and was thought to be bad luck. Queen Victoria promoted the stone in 1800s by giving opal jewelry to her children. In the middle ages, the stone was thought to make the wearer invisible, and was highly recommended to thieves.
Today, Australia is major source for opal and supplies abt 85% of the world's opal. Do not immerse in hot water or a sonic cleaner. Opal is graded by size/cut/rarity/base color/fire color/fire intensity/fire pattern and fire consistency. Opals have been imitated by Slocum Stone, a tough manmade glass, and in 1973, Gilson made an imitation opal in the laboratory, which is popular today. This item is in the category "Jewelry & Watches\Loose Diamonds & Gemstones\Loose Gemstones".
The seller is "deluxegems" and is located in this country: US. This item can be shipped worldwide.