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 Post subject: Garnets
PostPosted: Wed Dec 30, 2015 3:04 pm 
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Location: Central Queensland, Australia
Secured owners permission to go to a private property today that has a little deposit of garnets on it. They are mostly extremely heavily saturated red, almost black. However, there are also lighter, bright red and occasional pinks and even the odd green one among them. I have a good feeling about a gully that cuts through the surface deposit (the stones are no deeper than six inches down and many on the surface) and runs down the steep, rocky hillside - the garnets of course have a high SG and I can imagine the heavies being trapped around the boulders and rock bars in the gully. As far as I know, no one has ever excavated this gully. It will be all hand tools of course, I wasn't going to ask the owner if I could bring in a Bobcat, tommel and pulsator but if I'm right, nature has done the concentrating down for me - we'll see how we go :smt026


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 Post subject: Re: Garnets
PostPosted: Wed Dec 30, 2015 4:22 pm 
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Location: Wylie Texas but in Alaska for a while
You have all of the fun.
I made it to Australia once for a business trip to Alice Springs. (no need to ask where.... :roll: :roll: ). I had 2 weekends free, but could not find any one to go with me. I did not have a gps, and could not get one in time, so I took the advice which was not to go out alone. It was so fustrating.


I did get to go diving on the barrier reef. that was a good trip, but it was a shame to see that a lot of it had dies off.

I was in England when I learned to dive. My qualification dives were in the Red Sea. That was 15 years ago, and I do not remember seeing any die off. t is a pretty hard act to follow.

As I think about I have hit a pretty good bucket list.
- dove red sea and barrier reef
- gold panned in alaska
- saw aurora
- have a wonderful wife, 2 good kids and a grands


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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 5:39 am 
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Location: Central Queensland, Australia
That was a shame about not finding anyone to go to Hartz range with you, that place is a treasure trove. But yes, going alone isolated, arid places is certainly not recommended. We all love our sparkly rocks but I wouldn't risk my life for them.

The reef does have die-offs from time to time, coral bleaching, outbreaks of coral eating Crown of Thorns Starfish. Gladstone is at the southern end of the Great Barrier Reef but it's about 30 miles offshore down this end. We used to fish out there when I was a kid but I haven't been for many years.

Your bucket list looks pretty well complete Wilson - I think you've nailed the important things there, especially the last one.

I sometimes think about adding "extreme prospecting" to mine, say looking for fresh sapphires on the slopes of an active volcano :D


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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 6:09 am 
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Got to the property about 8 am. I couldn't drive the Navara down to the spot but the deposit begins right on the other side of the fence beside the road (it actually runs under the gravel road and goes to the property across the road but you aren't allowed over there). I picked up a few little red chips beside the road.

Humped all our gear down the steep, barren hillside to the gully. We set up under the only patch of shade on the whole hill, a few small scraggly trees had made a thicket in the bed of the gully part way down. To test my theory, we began excavating a pocket in the gully bed, digging down until we hit solid rock and scraping that. The second sieve produced the first result, a garnet about 10 or 12 carats (stil haven't weighed anything yet, too tired right now), intense red but a bit on the dark side.

The hole produced a few more garnets but vastly more of a shiny black substance that I'm still not certain of the identity. It looks like a dark garnet at first glance but is jet black with a very bright surface lustre and a slightly silvery, almost metallic tint. It isn't jet. It's damn heavy whatever it is. I haven't done an SG test yet either. I wonder if it could be melanite? Wherver the garnets are, this stuff is always accompanying them.

We got a few more in that hole and others. The temperature had been nice enough when we arrived but now was beginning to soar, a tropical summer and a barren rocky hillside facing into the western sun are not a good combination.

We worked our way down the gully and came to an exposed earth bank about six feet high. Close inspection showed that the bank was glittering with tiny black and a few red chips. We began raking material down from the bank which appears to be composed of broken schist and a crumbly red clay soil. Then first sieve yielded four garnets of facetable size and eye clean of inclusions. We spent the rest of our time scraping and sieving material from the bank and came away with quite a lot of black stuff and a reasonable number of garnets as well as a couple,of large chunks of massive garnet. One stone with apparently facetable material in in might go 30 carats or so.

We found no light red or any other coloured ones, they are all a deep, intense red. I'm not sure if i can get enough light in them for good faceted stones but I'll give it a go.

The black stuff might look good in a men's ring, it seems pretty hard and looks like it will take on a brilliant polish.

A hot, hard but satisfying day out :)


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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 4:12 pm 
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Thanks for the writeup! I've been looking forward to it. I'm glad you got some good material, though as you might guess I was hoping you'd get some of the coveted pinks or even a green. Still, another unidentified black material is not too bad a consolation prize.

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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 6:00 pm 
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Cheers Stephen. I know we can't usually identify a stone by a photograph alone, much less a picture-less description but do you think it's possible that the black material is simply a form of garnet, so packed with iron as to appear black? Using only the senses (I'll try and SG test later), it seems to share all the same properties as the garnet - a very brightly reflective surface lustre, very heavy, the rough pieces are the same "shape" as the garnet pieces and wherever the garnet is, this stuff is right there in the exact same spot as well - whenever there was a garnet in the sieve, this stuff was in there as well. It's definitely coming out of the same schist material.

The only differences are that it is opaque black and many of them have a slightly silvery, slightly metallic element to the brightly vitreous lustre. In fact, some of them resemble little pebbles of hematite, except for the obvious glassy look.

It was New Year's Eve last night here - I was too exhausted to sit up but when sister-in-law's hangover wears off :) I'll see if I can get her to work out the bugs with my photo uploading.


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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 6:26 pm 
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Melanite is a black andradite garnet. If the area's producing green garnets there are a limited range of possibilities, either andradite or grossular or something in between (discounting uvarovite for now). So I would think melanite would be a possibility, or maybe just an overdark almandine.

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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 8:05 pm 
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Ah ok, andradite. The garnets from this site I previously sent to a gemmologist were identified as pyrope. I had previously thought they were almandine but they don't look quite like almandine rough I've seen at gem shows - they are a straight out intense deep red, they don't have any of the slight purplish or burgundy tints I saw at the gem show.

But I was also told that with garnets, a pure variety isn't all that common and most are really a mixture. At this site I have previously found mostly deep red but also a lighter red, a definite pinkish and a single small yellowish-amber colour (but not this time). I have not found a green one myself but my father says a friend of his found a few there over a number of digging trips. The little yellow-amber one actually looks light green in the right sort of light.

Even these really deep red ones aren't all the same shade, some are a bit lighter with a bit better light penetration.

My thought is - never attempted this before - to test cut one with a simple pavilion with just one tier of facets at say, 36 degrees which should be about a degree and a half above critical. Then cut the crown with all facets below critical, hopefully more of the light striking the crown should enter rather than being reflected away. It should also result in a pretty shallow stone. Also, if I cut it in a triangular shape the light should not have as far to travel through the stone before reaching the other side. All of the small, shallow chips you find there are easily transparent, and while a dark stone will always be a dark stone, I'm hoping this combination might make a significant enough difference to at least get a stone that shows a bit of red and is not just black - getting light inside the stone is going to be the priority, brilliance will have to be secondary, as will getting back maximum carat weight. A long, narrow and shallow diamond shape would probably be the best. If that worked well enough, that might make a nice-looking pair of earrings


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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 10:11 pm 
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Location: Central Queensland, Australia
Largest facettable garnet: 37.25 carats. It isn't all clean but there should be a decent stone or two in it.

Next four largest facettable garnets: 12.85, 12.05, 11.9 and 9.4 carats respectively. A bit smaller than I thought but still decent size for faceting. Reasonable number of 2-5 carat stones, not sure how many.

Largest piece of black stuff: 71.3 carats. Seems to have a bit of a partial crystal shape.


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 Post subject: Re: Garnets
PostPosted: Thu Dec 31, 2015 11:11 pm 
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The deep, blocky pieces of rough are scarlet when backlit but I can see they would be nearly black as a stone faceted at normal angles. But the shallow pieces are transparent enough without any backlighting. Cross fingers this will work [-o<


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 Post subject: Re: Garnets
PostPosted: Wed Jan 06, 2016 12:08 pm 
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Marcos " shouga" worked for me on some dark aus garnets...


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 Post subject: Re: Garnets
PostPosted: Wed Jan 06, 2016 5:32 pm 
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It sounds like it will be a good collecting spot for a long time. I could live with red and maybe black garnet...... The black stuff sounds interesting. Maybe it will cabb if nothing else.


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 Post subject: Re: Garnets
PostPosted: Wed Jan 06, 2016 10:42 pm 
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Well it sort of worked...a bit. The stone displays red flashes in the right light but is essentially a very dark stone. But some people like stones that look like that. It did grow on me a bit after I saw in in bright natural light (not direct sunlight) it was dark and overcast the day I finished it.

I found one from a previous trip to the same area, it's a bit less saturated so worth a go. If I could take the generator, jackhammer, trommel and pulsator to the site, I could put through a significant volume of dirt and have more chance of finding more lighter red/pink/green ones that I know for a fact are there at the spot. I'm not sure what sort of reaction I would get from the property owner if I asked permission to bring in light machines though. Maybe after I've been back a few times, found a few nicely-coloured ones and made her a pair nice of earrings or something :D

This garnet came from the same spot a while back. It's about the lightest coloured stone I have found there myself, save the little amber-greenish piece. It's quite transparent without backlighting and you can put it down on the page of a book and easily read the print through it. I was hoping to find more with this as the minimum depth of saturation. I cabbed it, this was before I started faceting. The very "rustic" looking setting was my first ever attempt at silver smithing, so go easy on me :) I guess I could always remove it from the setting and facet it but I really would rather keep it as a memento.

Image


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 Post subject: Re: Garnets
PostPosted: Wed Jan 06, 2016 10:49 pm 
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Kingsolomon wrote:
Marcos " shouga" worked for me on some dark aus garnets...


Is there a link for that design Barney, I can't seem to find it?

Cheers


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 Post subject: Re: Garnets
PostPosted: Wed Jan 06, 2016 11:13 pm 
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But these are more typical of the stones from the site, these are some of the ones from the other day.......

Image

Nice colour when strongly backlit but none of the ones in my hand would pass a white paper test. Actually, photographing them backlit shows them purplish when they aren't really that colour, it's an intense red to blood red .......

Image


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