Australian Opal

Australia’s national gemstone is the opal, a stone famous across the world for its brilliant colours. The origins of opal are told in a number of Aboriginal Dreamtime stories. (https://www.goodopalco.com/2021/05/17/dreamtime-origins-of-opal/)

Opals are multi-coloured and consist of small spheres of silica arranged in a regular pattern, with water between the spheres. The spheres diffract white light, breaking it up into the colours of the spectrum. This process is called ‘opalescence’. Larger spheres provide all colours, smaller ones only blues and greens. Opals that have a predominantly red colour are very rare as they only occur where larger silica spheres were deposited. As the water was absorbed back into the clay, the coloured silica hardened over millions of years and resulted in the opal gemstones that Australia is known for. The source of Australian opals is largely fossil and mineral. Opals found outside of Australia have a mostly volcanic base.(http://www.gemstory.com.au/advanced1-how-opal-is-formed.html)

Australian opals were discovered during the late 1800’s. By 1932, Australia took over as the major producer of opals in the world and remains the largest producer to this day. Opal is found around the world (Brazil, Mexico, Honduras and the western US) however, Australia produces 95% of the world’s precious opal.

Opal was first mined commercially in Queensland in 1875 and later at White Cliffs in NSW. Today, Coober Pedy, in South Australia, is the main producer of white opal. Other centres in South Australia include Andamooka and Mintabie. Lightning Ridge, in New South Wales, is renowned for black opal, and White Cliffs was a large producer of high quality opal. Boulder opals (opals in concretionary ironstone) are mined in Queensland from numerous localities in an area extending from the Eulo and Cunnamulla district in the south for a distance of over 700 km to Kynuna in the north. The towns of Quilpie, Yowah and Winton are the main opal mining centres.

Australian opals are ethically sourced, are of superior quality, and are in high demand worldwide.

Types of Opal found in Australia

Boulder Opal

Boulder opal is cut with the natural host rock, ironstone, attached. Variations are seam boulder opal, matrix boulder opal and pipe boulder opal. It is popular among opal jewellery designers around the world.

White Opal

White opals have a white or milky colour. It is the most common type of opal due to the large amount of white opal mined. Many people think of white opal when they think of Australian opal.

Black Opal

Black opals are rare and quite valuable. Black opal has a black or a grey base and can have colours ranging from brilliant red through to greens, blues and purples. Black opal can be found as a ‘nobby’ or as a ‘seam’.