At the Billabong Blue mine, sapphire is found in the gravel layer along stream channels. The larger gravels help to trap more sapphires. Photo by Andrew Lucas/GIA.
A truck loaded with sapphire-bearing clay feeds the washing plant. Two trucks work at the same time. Extra material is stockpiled near the washing plant for future processing. Photo by Vincent Pardieu/GIA.
Selected samples from the concentrate produced in the Kings Plains sapphire mine. Photo by Vincent Pardieu/GIA.
Part of the ore processing involves removal of sticky, claylike material from the gravels. Photo by Andrew Lucas/GIA.
Sapphire crystals are visible in the concentrates from the jig. This concentrate will be transported to be magnetically separated before the final handpicking of sapphires. Photo by Andrew Lucas/GIA.
The Australians were first to use a magnetic separator to further process sapphire concentrates from the jig. The intensity of the magnetic force can be adjusted manually for the best fit. Photo by Vincent Pardieu/GIA.
The sapphire-bearing layer in the Kings Plains mine is about 6 meters below the topsoil. The clay-like nature of this layer suggests that the layers may consist of alternating volcanic ashes. Multiple sapphire-bearing layers like this occur in this region. Photo by Andrew Lucas/GIA.
With over a hundred years of sapphire mining history, the locals in the Rubyvale-Anakie region are very proud of their sapphire culture. Photo by Andrew Lucas/GIA.
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GIA field gemologists Andrew Lucas (left) and Vincent Pardieu (right) and Gems & Gemology technical editor Tao Hsu (middle) visited an underground sapphire mine in Rubyvale, Queensland. Photo by Victoria Raynaud/GIA.
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