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How much gold in a specie??
Topic Started: Tuesday 9-10-2007, 12:44 (210 Views)
nuggetykath-68
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Hi again......I would very much like some replies please.

The specie weighs 109.1 [dry weight]
74.9 [wet weight.....done correctly! suspended in water etc]

How much gold?????

Marc did three different methods & came up with three different readings BUT only approx 2grms the difference.

Doesn't it make a difference if the gold is in ironstone, quartz etc??
Any info will be appreciated.

Hoping Nightjar can post the photos I am about to send him!!
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davsgold
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Hi Kath

It would make a difference if the specie is ironstone / gold, as quartz has an SG of 2.6 and ironstone is heavier than this. Most of the calculation tables just use the quartz at 2.6 to work out the gold to rock ratio.

Here is the one I use, you may already have it.

http://www.gold-nuggets.org/specific-gravity-test.htm
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nuggetykath-68
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Hi Dave,

Many thanks for your reply, I shall go & check if we have this particular one.

Find these things very interesting. Amazing how some species appear at first to have little gold but on further investigation there is a lot more inside some of them.Now THAT makes me smile ALL DAY!!! :D

cheers,
Kath
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Nightjar
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Hello Kath,
Here goes, my calculation indicates 24.88G/AU.
It is very difficult to get an accurate content when there is a combination of quartz & iron stone.
One interesting fact I have found when getting the "wet weight" that it varies between tap water & distilled water.
Anyway species are great to keep and are valued more in their natural state than if they are dollied to remove the AU.
Good luck with your next trip.
Regards
Peter
Good luck & safe travels
Peter


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nuggetykath-68
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Thanks Peter, found it interesting about the different waters..we used water from the van tank. Your amount is soooo close to ours so we MUST be on the right track!! Agree about the contents of the stones..quartz etc etc like Dav said.
Yes we often keep the species as a whole but the hubby was very curious about that specie as could see very little gold, had to REALLY look....it was just the signal that prompted me to keep it..thankgoodness I did! Also dug another specie which didnot show ANY gold..yep the guys cracked it opened & inside was a beautiful nugget.

Cheers,
Kath
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Nightjar
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Hi all,
Found this old post with reference to gold content in species.
Does anyone have a new formula?
While away last trip we did some experiementing with this formula:
Wet weight X 3.1 minus dry weight X 1.9

Weighed a piece of quartz then a clean nugget. So we had a definite weight for both.
Looped a length of cotton around both the nugget and the quartz and got the wet weight.
Applied the above formula and the resulting weight of gold in the quartz was no where near the known gold weight?
Have brought a small piece of quartz home with me and I'm going to play around with the formula to try and get a more accurate result.

If anyone has a tried and proven formula would be very interested in reading about it.

Cheers
Peter
Good luck & safe travels
Peter


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silverback
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Peter, im not sure but i think there is a very old post on finders from an old well respected prospector who passed away last year i think.i forget how i got to it but next time im lurking there i will see if i can find it.
All the best,
Peter
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Nightjar
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Thanks Peter,
Feel sure other members would appreciate the info as well.

cheers
Good luck & safe travels
Peter


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silverback
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Hi Peter, found it!seems you knew the guy,Hakey :D anyhow it was way back in nov 2003,use the search under Hakey and lots pop up.seems he was a bit cantankerous at times but then we all get like that as we get older :D :D :ermm:
All the best,
Peter
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Nightjar
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Thanks for the info Peter, have found a post with another method, looks complicated but will give it a go and post results.

Cheers
Peter
Good luck & safe travels
Peter


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Topcat
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Hi Peter,

Have you tried this method:

The Specific Gravity Test (used to calculate the gold content of gold nuggets that contain a mixture of gold and other materials)
In this example of the specific gravity test, we use gold mixed with quartz.
Simply put, the formula is 3.1 x the weight in water, minus 1.9 x the weight in air:

Wet nugget weighs 74.5 grams x 3.1 = 230.95
Dry nugget weighs 96 grams x 1.9 = 182.4

230.95 - 182.4 = 48.55
31.1 = number of grams per ounce
48.55 / 31.1 = 1.56 ounces of gold

Original dry weight = 96 grams / 31.1 = 3.08 ounces.
Subtract the difference between the wet and the dry:
3.08 ounces - 1.56 ounces = 1.52 ounces.
Therefore what is left is 1.52 ounces of quartz.

"Wet" = weight in water - Put container of water (enough water to cover nugget) on scale. Tare (zero) out scale.
Hang nugget by string in water. Note weight.

The specific gravity for gold is 19.3.
The specific gravity for quartz is 2.65.
The ratio between gold and quartz is 7.28 X.

Also here is a website that gives specific gravities for most materials:

http://www.reade.com/Particle_Briefings/spec_gra2.html

Cheers

Ted
Cheers,

Ted


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Nightjar
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Thanks Ted,
However you will see above that this was the formula we have been using and it is not accurate.

Cheers
Peter
Good luck & safe travels
Peter


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thedigger
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Another method to weigh speci

First weigh speci

Fill a container with water (to suit the specimen )then lower your specimen in the water on a fine thread,it will over flow the container of water,then remove your speci.
Then add small quartz stones or iron stones which ever your speci is made of,until the water gets to the point of flowing over.

Remove the stones and weigh,and subtract from the original,and that will be the amount gold in the speci.

Regards Frank
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kevlorraine2
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great one frank THE DIGGER even i can follow that one.

it will be close enough out in the paddock to quell arguements and keep a smile on your dile... kev :)
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mulgadansa
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Hello All
Ted, great post, from memory I think you were spot on with your summation on SG testing. We used this method a fair bit back in the 70's/80's when we were doing it full time.
The only problem I struck was that quartz and other materials have varying SG's depending on there composition, this included the gold I think, given the huge range of purety of nugget that you find. I recall that we took samples of the host quartz (from nearby where the speci was found) or whatever the material was that did not contain any gold, determined it's actual SG and then applied that to the test you described. Can't for the life of me remember how we got that SG but.
You also have an insurmountable problem if the material is at all conglomerate in nature but the dolly pot never lies :D
cheers
Brett
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