Australian Black Opal Loose (Unset ) 6.00 carat - 18.00 x 10.00 x 7.00 mm Classified by the Opal industry as Natural Opal Type 1 Genuine Australian Black Opals are the most valuable and popular of all Opals and account for around 5% of Opals and is found at Lightning Ridge in Northern New South Wales. https://vimeo.com/556999018