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Monday 2 September 2013

BACK CREEK, PINKETT NEAR GLEN INNES, NSW AUSTRALIA

Back Creek is the first major creek south of Yarrow Creek on the Pinkett road, about 25km south east of Glen Innes. As seen from the road, there are numerous granite outcrops, especially on the eastern side. Near the point at which the creek moves away from the road, outcrops disappear and sand appears to make up the creek bed from here on. At the point where the Pretty Valley road crosses Back Creek there is nothing to be seen but sand. All this country is private property, needless to say, so access will need to be arranged for fossicking.

The above quote comes from the book “Exploration Data Package for the Glen Innes 1:100,000 Sheet Area” by RE Brown (1995). The DIGS reference is GS1995/231. It strongly suggests that good gemstones are to be found in these south eastern areas. Our numerous trips to Yarrow Creek confirm that this is indeed true; however there have been sapphire mines at various places along the Yarrow where sufficient accumulation of wash has happened. 

Yarrow Creek is shown as a sapphire bearing stream in the following references:

Sapphire in NSW 1983 DIGS reference Information Brochure 40, Sapphire in NSW 1995 DIGS Information Brochure 41, Quarterly Notes 103 (1997) DIGS reference QN 103, Records of the Geological Survey of New South Wales, Volume14, Part 1 by AA McNevin (1972) DIGS Records 14(1) . 

Back Creek topaz
Interestingly, neither Pretty Valley, nor Rainy Swamp nor Back Creek appear on any of the maps in these references. In the case of Rainy Swamp sapphires were certainly mined there. Pretty Valley appeared to be virgin when we first investigated it. Back Creek showed signs of old prospecting along both of its major tributaries upstream of the Pinkett road. Yet no trace could be found in DIGS of any mining or prospecting in these three areas. All three have produced good gemstones on our many visits.

I have mentioned in the Blog entries on both Rainy Swamp and Pretty Valley that their gemstones differ from those in Yarrow Creek, but resemble each other. The same is true for the gems from Back Creek. Indeed, I think it likely that the Rainy Swamp deposit is a former course of Back Creek. It would not be difficult to imagine Back Creek having formerly flowed where Bladey Grass Creek is today (Pretty Valley).

The typical wash from Back Creek produces a concentrate containing sapphire, zircon, spinel, tourmaline, topaz and cassiterite. There is a great deal of clear and smoky quartz. The topaz has been found in pieces up to 150 carats, mostly colourless but with some blue and apricot coloured stones. There is a lot of black tourmaline and I have seen one piece only of gemmy tourmaline. The sapphire is mostly opaque but clear stones of all the usual colours turn up. There is a little beryl to be found as well.
Gemmy tourmaline from Back Creek
I have seen two “bonanzas” found there when dozens of cutters suddenly appeared in a relatively small area. I was involved in finding a third and it was extraordinary to come upon wash peppered with all the gems mentioned when it was normal to see just a few in the sieve. That’s what gem hunting is all about and I have to say that it was a sad day when we lost access to the best part of the creek in 2002. 

I have no photos of fossicking at Back Creek, unfortunately, and just a few of some finds from there. I’m looking forward to reading about future successes by readers of this Blog. 

You can experience fossicking around Glen Innes through my You Tube site until you pay the area a visit. Click here. I also have playlists on Glen Innes, the Blue Mountains and New Zealand.

All New England and other Geology blogs and videos
Back Creek topaz

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