You can go to the opal fields and find opal in the tailings that have been missed by miners.
From Australian Geographic
OPAL – STUNNINGLY BEAUTIFUL and quintessentially Australian – is our national gem.
Unique among its peers, precious opal is a glassy, translucent stone that refracts light in brilliant colours, which flash and change as it is viewed from different angles.
More than 90 per cent of precious opal is from Australia; here the geological conditions around the once vast Eromanga Sea favoured its creation over millions of years from silica deposits in subterranean pockets. Opal fields can be found around the shores of this prehistoric ocean, once the province of giant reptiles.
Opal mining towns
Four towns in particular – Coober Pedy, Andamooka, White Cliffs and Lightning Ridge – are synonymous with opal mining, and all have stark landscapes, pockmarked with shafts and mullock heaps.
Today they thrive on tourism as much as mining, and are rich places to experience Australia’s mining heritage and outback way of life, as well as have a go at ‘noodling’ or ‘specking’ for opals.
Opal comes in a variety of colours and styles. Most common is opaque potch, which lacks precious opal’s colourful play of light. Translucent crystal opal is found in all fields.
Black opal, sometimes with deep-red colouration, is found at Lightning Ridge and is the most valuable; light opal comes from South Australia and New South Wales; Queensland produces boulder opal, formed within brown ironstone.
Opal is also found in places such as the USA, Ethiopia, Honduras, Mexico and Brazil, but Australian opal is still regarded as the most valuable.
Exploring for Boulder Opal on the Eromanga opal field – far south western Queensland, Australia. Video by Sandy Kent, July 2019. iPhone 7+. Be sure to watch Part 2 as well.
Yowah Opal town this is a great place to visit. Camping and caravan park and fuel are available. ARTESIAN Baths, Mine Tours & Fossicking and lots more to do. Have a devonshire tea with Colin and Georgina! Mention MNF sent you and boy will you get looked after!!