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 Post subject: Springsure labradorite
PostPosted: Mon Jun 27, 2016 11:27 pm 
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Heading back out to Springsure on Thursday for a full days dig on Friday. Accommodation in the town is booked - dad is too old to rough it anymore and while I'm still capable, I'm starting to feel less inclined myself :) Anyway, it's on private property with general permission given to the public to dig but no camping is allowed. $5 per car per day is a mere pittance to pay for the permit picked up at the local hardware store and the money is donated to the local ambulance fund.

Forecast is for clear skies and a daytime maximum of 20 Celsius - perfect digging weather. I've only ever sieved the sandy gravel in the creek bed, this time I'm going to rake the crumbly black basaltic soil that the stones are weathering out of.

I really like the stuff - it facets a bright, champagne-coloured stone that is regularly selected as favourite when I show people a tray of mixed stones. But for some reason it seems very difficult to photograph and it's hard to take a photo that does it justice (of course, I have trouble snapping most faceted stones).

Anyway, with a full day to dig - I've only ever spent a couple of hours there on a couple of occasions on the way home from the sapphire field - hopefully I'll get some decent bits. There was an opalised wood deposit close by but somebody went in their with an excavator and dump truck without the property owners consent and made of with several tonnes of material. The understandably outraged property owner then closed the site to the public :( But maybe there's other bits of it around, we found a nodule of what looks to be a common opal of some kind in the creek bed at the labradorite site, maybe we'll turn up something a bit different.


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 Post subject: Re: Springsure labradorite
PostPosted: Tue Jun 28, 2016 12:35 am 
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Good luck

I tried to meet up with my dad a few years ago at gold and gem place that was between us. Part way there he decided he could make the trip and went back home.

I did a day in the gold pile then brougt the concentrate and slan additional 5 bucks up to his farm. We set up the mini gild hog using his pond and spent a few hours gold mi ing at his place. The gems from that trip are what started me faceting.

When i get back to dallas i have to make a trip back to the farm to bring back the hydraulic cylinder grom his tractor that i tok off to get repaired. I think i will dig up the gems from that trip and bring the facet machine and cut a stone with him.

Enjoy time with him while you can.


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 Post subject: Re: Springsure labradorite
PostPosted: Wed Jun 29, 2016 4:06 pm 
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Ok, I'm off, hopefully to bring home a swag of labradorite and maybe even something else. Back in a couple of days!


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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 6:06 pm 
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After checking into the motel and grabbing our permits in Springsure, we arrived at the dig site around 1:00pm. The dirt road is built over basaltic black soil - a few drops of rain and it becomes impassable. But the weather was fine and the road itself was in good condition, people had obviously had the sense to not try and drive on it during the last bit of rain a week or so ago. The turn off the road is marked by an ancient, rusting tractor left parked, probably where it finally gave up the ghost, with a sign on a tree saying "no unauthorised fossicking, no camping".

Two wheel ruts lead off the main road for a couple of hundred yards, ending beside the gully where the material is found.

Image

The gully bed is full of old and new diggings. In the gully, the stones are in a mixture of black soil and sand and gravel, which goes through the sieve without too much trouble when dry. Problem for us was that it was still damp from the recent rain and while it did go through the sieve, everything was left with a coating of soil, making it a bit difficult to see the stones. First time I've seen the ground damp at that place. I rarely dry sieve, I nearly always take washing water and a wash drum with me, first time I don't and I find I need it!

Image

We did get some pieces but it was getting late and we decided to head back to town and come back in the morning and try a different approach. As we drove back along the road, we spotted an echidna waddling along the roadside. By the time we turned around and came back, he had engaged the echidna defence mechanism, which is to part-bury themselves in the ground, hiding their soft underbelly and leaving only a mass of sharp spines sticking up. But this one actually stuck his head up slightly for the photo.

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Next morning, headed back out and decided to try up on the high bank above the gully, in the hope that the ground might be a little drier up there. I stopped when I saw a small piece lying on the surface and decided to have a scratch there.

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So we started scraping the ground there, which was indeed much drier and almost powdery compared to the stuff in the gully bed. A few more small bits, and then this rather larger piece popped to the surface.

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I don't know how big the stuff comes. This is the biggest bit I've seen myself. Better still, apart from a few shallow surface blemishes it appears near-flawless. It's a little over an inch across. Not sure how to approach faceting it yet, when the crappy surface bits are removed it looks like it would be a square - maybe a big Barion square cushion? Doubt I'd ever set it, Just set it in a box and put it in a display case.

Image


Inspired by that find, we scraped down the surface of that area , making it down about six inches before the ground began to harden. Now this stuff does not have a high SG and does not accumulate in pockets around boulders or any low-lying spots - yet, we seemed to have hit a heavy concentration of it, just in that one little area. By the end of the day, we had retrieved around five thousand carats of material.

Image

It looks like a lot but a high percentage is either cracked or a bit small. Nonetheless, we did get some decent stones and we were happy. It was a good trip :)


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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 7:27 pm 
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very well done.

It looks like there will be some nice stones from it.

I look forward to seeing them posted.


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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 7:53 pm 
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Nice haul. It looks identical to the yellowish labradorite "sunstone" available in large quantities in Oregon, USA. The material produces amazingly bright and attractive faceted stones despite the low R.I. and other properties. Looks like you've got a lot of cutting ahead of you.

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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 8:18 pm 
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ROM wrote:
Nice haul. It looks identical to the yellowish labradorite "sunstone" available in large quantities in Oregon, USA. The material produces amazingly bright and attractive faceted stones despite the low R.I. and other properties. Looks like you've got a lot of cutting ahead of you.


I think it would be closely related stuff ROM. It's an orthoclase feldspar. And yes, this stuff does facet surprisingly very bright and attractive stones, even with it's low R.I. Whenever I show people a tray of mixed faceted stones, this stuff is regularly selected as favourite.

It's interesting to wonder why this material and the Oregon material both facet such bright stones when the R.I. says it should be otherwise. Could it be microscopic inclusions (albite?) reflecting the light? A lot of the cracked pieces show bands of white material along cleavage cracks that look bright silver and reflective in the sun and I did cab a couple of pieces and they appeared to show a weak adularesence.

The hardware store where you buy the permits has some rough and faceted pieces as examples. One of the faceted stones was very nice, much more yellow than usual. It almost looked like a yellow sapphire. I have found a few small orange pieces but they weren't faceting grade unfortunately.


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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 8:21 pm 
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Looks like you've got a lot of cutting ahead of you.


Dad found a nice piece, almost as big as the one in the photo. Roughly triangular in shape, I think Voltini's "Tribal" would be a good design for it. Might start today.

The only problem with finding thousands of carats of faceting material is that you then have to sit down and sort through thousands of carats of material to grade it - tedious!! :shock:


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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 9:40 pm 
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The feldspars are in solid solution and have arbitrary dividing lines between varieties based on subtle chemical differences. It's very difficult to ID many of them without testing. As you probably know the Oregon sunstones are blessed with natural copper inclusions that provide an array of colors and optical effects in the finer grades, unlike the "red andesine" scam stones of a few years ago that had been treated by diffusion in China.

I've often wondered about the unusual optical performance and have no explanation. Maybe someone here knows. I first noticed it in some ultra-bright faceted feldspars collected from a volcanic site near the Spencer Opal location in Idaho, USA. I was very pleasantly surprised when I cut my first yellowish Oregon stone. Too bad they're so abundant, i.e. inexpensive. I used to give calibrated rounds away as lagniappes with some purchases from my website.

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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 10:33 pm 
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I picked up a few pieces of sun stone at a show last year. the ones I have are very zoned, with the color in the center. It looks like Left's material is more uniform in color.

I have not gotten the courage to cut the sun stone yet. At least when I ct my synthetic, I am only risking a few cents, and lot of time...... I bought out a supply of synthetic from someone that had bought out a jewlery store. He wanted the tools, and let about 60 boules go pretty cheap. So I do not mind messing them up.


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 Post subject: Re: Springsure labradorite
PostPosted: Fri Jul 01, 2016 11:02 pm 
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Wilson, it sounds like you have Oregon sunstone with schiller, not the plain yellow labradorite. These two sites might give you some pointers on identifying which kind you have and faceting or carving them:

http://www.dustdevilmining.com/about-oregon-sunstone/

http://facetingacademy.com/learn-faceti ... -schiller/

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 Post subject: Re: Springsure labradorite
PostPosted: Sat Jul 02, 2016 7:23 am 
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Too bad they're so abundant, i.e. inexpensive. I used to give calibrated rounds away as lagniappes with some purchases from my website.


This material is often used by lapidary clubs in Central Queensland as a stone to each faceting to beginners, presumably because it is not hard to get a hold of and because it usually cuts and polishes easily. Shame, such a very nice-looking stone but worth practically nothing because of it's abundance. I don't know how big the deposit is, it seems to be restricted to a very small "valley" - a low-lying tract of land between to very low ridges, the tops of which have rock outcrops with bits of the feldspar embedded in them. You can pick it up on the road where it crosses the valley but half a mile outside I stopped and walked the road and found none. But within the valley itself, there's heaps.

A fair bit of this material actually has reflective silver inclusions though it, in neat parallel lines along the cleavage planes, the bigger inclusions have rainbow-reflections. But most people I know of just toss those ones aside and only facet the mono-coloured, inclusion free pieces. I might have to have a go at faceting some of these.

I did cab a couple and they showed a weak adularescence.


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 Post subject: Re: Springsure labradorite
PostPosted: Sat Jul 02, 2016 9:55 am 
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Lefty wrote:
It's an orthoclase feldspar.

Quite note: it's a plagioclase feldspar, not orthoclase. Orthoclase is a potassium feldspar, which would not be at all happy in a basalt like this.

The white schiller sounds a bit like what you see in some Mexican bytownite. It can be used to good effect if oriented face up to the table.

I suspect you may change your mind about setting the big one once it's cut. The small ones are bright, yes, but it's the big ones that really step up and outperform expectations. My mom has a 40 ct one set in a pendant that we found in Oregon, and it looks ridiculously nice. Nobody guesses it's labradorite!

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 Post subject: Re: Springsure labradorite
PostPosted: Sat Jul 02, 2016 5:50 pm 
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Ok, so potassium and basalt-derived don't go together in feldspars. I could really use someone like yourself to accompany me on my expeditions Stephen :) So much igneous countryside, so much gemmy potential I reckon. This spot is not all that far from the Anakie sapphire field and just like that area, there are volcanic plugs sticking up all over the place. But I don't think they are the same run of volcanoes - I can't sum it up in geological terms but they just look different to the Anakie ones, the ground looks different somehow. The rocks you see in the sapphire wash and just lying on the surface are not present here, they are different altogether.

I brought home - I left it in Dad's car but I will get it and take a photo - a piece of what I assume to be some kind of scoria from the ridge crest. It's a bright pinkish-red in colour and so perforated that it looks like honeycomb. It's very light, obviously a good part of it's volume is just air. Never seen that stuff on the Anakie field.

I went down to the workshop last night and took out the container of small and reject pieces and found a piece that when oriented a certain way, produces a ghostly, billowing reflection as you gently rock it back and forth. I guess it would be a moonstone except that instead of being like the ones I've seen which are colourless with a blue shiller, this is light honey-coloured with a silver shiller. I'll cab it but it will be small, the size of my little fingernail. Next time I'll be looking out for bigger bits like this one.

I started faceting the second-largest piece, even with only the pavilion finished I can see just how remarkably bright the finished stone will be. It actually has small silver inclusions, I'll see how they look when it comes off the dop today.


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 Post subject: Re: Springsure labradorite
PostPosted: Sun Jul 03, 2016 9:27 am 
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Faceted stone looks nice.

Made another discovery - I've been throwing away moonstone because I didn't know what the rough stone looked like. Most of the translucent white pieces of labradorite we left lying there because they obviously were no good for faceting. I did keep a couple as specimens. I could see a bit of a sheen on this piece in a certain direction. When I put a shallow curve on the top, the whole stone became strongly adularescent silver-blue - much more pronounced than the other piece. Definitely what I would call moonstone.

I then proceeded to ruin it by unknowingly grinding down through the shiller plane - the translucent stone suddenly became completely transparent and the shiller faded dramatically #-o #-o #-o The stupid thing is that it wasn't just restricted to a thin plane, it made up about 75% of the thickness of the stone. The shiller seemed to display better with a low dome so I decided to cut it down and ground through that layer and into the thinner layer of transparent labradorite. Had I made the other side the bottom of the cab it would have been fine.

Anyway, I know what I'm looking for now and will be keeping the white pieces next time.


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