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The Geelong Gem & Mineral Club Articles section.
Article ID : 65
Audience : Default
Version 1.00.01
Published Date: 2010/12/3 16:10:00
Reads : 13791

Marble Bar is 200km from the Highway and is a small outback town that takes its name from the Marble Bar. The spectacular red, white and blue/black striped rock (locally known as the “Bar” was named by early pastoralists because they thought it was marble and because it blocked the flow of the Coongan River.

The Marble Bar is really Jasper, or more correctly very fine grained Silica (SiO2) The different colours in the rock come from trace amounts of mineral impurities, including iron (Hematite) making the red layers and pyrites and carbonaceous material that makes the blue/black layers, the white layers are pure Silica.

Best results when viewing the “Bar” are obtained by throwing a bucket of water over the face of the rock enhancing the colours. As far as getting a chunk to convert into cabochons goes, forget it, as a $10,000 fine is enforced for those who stray with the pick. All is not lost however; a fossicking area with easy access is provided. The colours do not seem as bright; this could be due to the actual bar being wet and cleaned from time to time. The Jasper/Chert reef goes for nearly 100km so there is no shortage of the rock.

The Comet Goldmine is now a tourist display/shop area. No real mining takes place there except out of the tourist pockets. They have a good variety of WA specimens on show and a few pieces of locally made jewellery. We hope that none of our Gem Show Dealers have seen the prices they have on their samples.

After spending a week in and around Marble Bar, (3 days would have been plenty) we headed back to the coast straight to Point Sampson as we wanted to check out some fossicking sites in Roebourne, Karratha & Dampier.

Once again, checking out the info given to us by Laurie Molloy and our mud maps we pinpointed a couple of likely spots to get Picture Jasper & Pilbara Jade (Prase). Easy to identify spots were hard to locate on the ground. Change has occurred since the mud maps were drawn as many places were closed because of mining leases & prohibited areas. Rio Tinto has a whole tract of land stitched up. We did however manage to find a hillside full of Picture Jasper which is just outside of Point Sampson on the Southern side of the estuary, on the left hand side of the road going toward Roebourne, tonnes of it. The prase we found was next to the old Drive in Theatre site as you drive in to Karratha, practically on the main road scattered everywhere.

Other places were extremely difficult to find given the effects of suburban sprawl, mining leases, new railway tracks and prohibited areas, however, we did manage to accumulate a few more rocks.

Our next move was to be Karijini NP, Wittenoon and Tom Price. Our aim was to get some Tiger Eye and different types of Jasper. (not from the NP of course)

D&P

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