Mintabie, South Australia is located about 240km northwest of Coober Pedy.
In the mid 1980s, the township of Mintabie surpassed Coober Pedy for 5 or so years in supplying gem grade precious opal to the world. In its peak there were around 70 bulldozers working the Mintabie fields and the amount of diesel trucked into the town at that point was staggering. Unfortunately the Government has closed down the Mintabie township and opal fields and getting you hands on some nice Mintabie opal is getting harder and harder.
Opal is found in the palaeozoic rocks, in the Mintabie silicified sandstone.
Rough Mintabie slices
The Mintabie beds are so hard to work due to silicification that explosives and large bulldozers are required to break up the sandstone beds. Spotters walk behind the rippers of the large bulldozers looking for any traces of opal that has been unearthed.
Ocean blue Mintabie pendant set in 9ct gold!!
Made by me at Opal Quest
Mintabie verticals (rough)
Polished Mintabie vertical
The opal is found in the horizontal and vertical joins of the sandstone beds extending from just near the surface down to a depth of around 30 meters.
Mintabie opal is often noted to display dark and light coloured bands, with most of its colours showing in the light, crystal bands. The light opal crystal is then cut to display its bright flashes of colour over the dark potch backing. This is known as Mintabie black and semi black opal.
While some of Mintabie opal has a play of colours in the black potch, similar to black opal found in Lightning Ridge, there is also the milky white opal, semi translucent jelly opal and blue-black potch opal.
Because of the layered structure of the sandstone beds, much of the opal forms in narrow, semi horizontal veins or seams. Thickness can vary from 1mm up to 10mm but has on the rare occasion been found much thicker.
After the earth is ripped with a bulldozer, any slabs that are found to contain opal are collected and then broken up into smaller pieces by hand. Any precious opal located within these pieces are removed for cutting. Of particular value is MIntabie opal showing a black body, which has sold for thousands of dollars per ounce and when cut has fetched $10,000 AUD per carat.
Since its peak in the 1980s mining has noticeably declined. There is now very little opal coming out of Mintabie, which makes every piece of Mintabie opal exciting when you can get your hands on some!
Mintabie opal (white/grey base)
Check out our range of Mintabie opal at www.opalquest.com
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