Gold Buyers Australia - Retail Shops - Beware

What is a density machine and how does it work? How accurate is it?

I always thought the only way to correctly test golds purity was through assay?

I believe true Assay is where it gets melted. I think you're referring to Specific gravity or Xray testing.

you can read up on it here

http://www.nqminersden.com/specific.htm
http://casanovasadventures.com/catalog/metaldetector/p10512.htm

Cash for Old Gold wrote:I believe true Assay is where it gets melted. I think you're referring to Specific gravity or Xray testing.

you can read up on it here

http://www.nqminersden.com/specific.htm
http://casanovasadventures.com/catalog/metaldetector/p10512.htm

No I understand specific gravity...ie: determining the weight of gold in a specimin.
Yes Assay where gold is melted, impurities removed and the actual purity of the original nugget can be determined.

From your second link... "Specific gravity is a measure of the density of a mineral. It is a useful property that sometimes becomes the only way to distinguish some minerals without laboratory or optical techniques".

Specific gravity or determining the density does not give you the purity which is what an assay does.

What I want to know is what is a density machine, how does it work, is it accurate, how do you determine purity via density.
Neither of your links answered these questions.

many thanks

MT

A xrf scanner will give you the exact % of most minerals present in a sample
and does it by x-ray and flouresence giving a total gold/copper/silver/nickel etc readout in percentages,
see the link below

http://www.quickshotxrf.com/quickshot-xrf-analyzers

This is but one of the many brands and types on the market,they can cost up to $95.000 ea
so none of the shonky stall holders would have one and they would only guess the gold content in their
advantage not ours...... dodgey..


Pete in WA

thanks Pete!
new question...Cash For Old Gold....do you have an XRF Scanner?

MT

can ya hear the tumbleweeds rolling past ya hahahahaha,
lets wait n see the reply ay.


Pete in W bloody Ay

Most likely one of these sort of things, which are only a fancy specific gravity scale.

http://www.alibaba.com/product-gs/291860436/300g_0_01g_Portable_Gold_Testing.html

The biggest problem arrises when using these type of machines for testing gold nuggets is that, how much of the nugget has quartz and then in the same nugget there is some ironstone and a bit of iron oxide. All these impurites of quarts ironstone and iron oxide etc have different specific gravities, and they will all be in varying quantities in different nuggets.

It may work well on jewellery when the most common combination is 24k=99.9% or 22k=91.7% and 18k=75.0% etc, but it also says that when using this machine to test jewellery to remove any stones as this will give a false reading if you dont.

So I wonder how they will go about removing the quarts and ironstone ect form the native gold nugget so as not to give a false reading.

G;day Davsgold

I believe a specific gravity test is also done with a specie, combining the specific gravity for qrtz/iron then the
XRF is scanned over the gold to give just the purity of the gold only, and the calculation is then worked out at gold purity vs gold weight in the sample.
Also the XRF does not show qrtz in the scan only metalic minerals.

Peter in WA

Jeez

Seems this thread just died in the ass once some serious questions
where posed to "cash for old gold".....

pete in WA

So if someone on this forum opened up their own chain of gold and silver and platinum buying shops and offered a 20% premium on what the other guys offer. You would be the new gold buying kings around australia and still make a hansome profit out of it. While still ripping off the public. Plus i do not see too many people whinging and whineing about paying about $6500 for a GPX5000 when its true worth is about $730.

explorer wrote:Plus i do not see too many people whinging and whineing about paying about $6500 for a GPX5000 when its true worth is about $730.

I ain't looking to open a can of worms here and forgive my ignorance, but why do you say that?

Cheers,

Nature Pete.

Sorry beepinpete flat out busy with work. Yes you are right Xray Machine first to identify purity then Density scales to calculate the total gold weight in the nugget.

Sorry guys- keep to the topic

I'll only say that Explorer has mistaken materials in a detector as its true worth, without taking into account Research & Development, and the company costs in marketing and distribution.

Lets leave it there.

Jeff

There are lots of options if you do the research. I've come across ABC bullion in sydney, they will send your loot off for assaying and smeltering, the assaying uses approx 5gs and smeltering costs $165 or so. You can take delivery of your gold as bullion form and or as a cheque. So if you have a few bits its worth considering as there are usually much better deals than the shopping centre rip offs.

As always do your research.

P.S. I don't work for them.

@ "Cash for Old Gold" what you were offering does sound like a good deal.

Mat

I buy gold and I pay $35-$42 a gram depending on shape and area that it was sourced from. Pilbara gold is my first preference.
Its a case of take it or leave it.
Size 9grams - 15grams.
No species--- no rock impurity ---just gold nuggets.

Regards
Oneday69

Hi, I'm new here. Sometimes go to Marysborough as I have a mate there for prospecting; maybe catch up with members from here over there??
Anyway, at last I found somewhere that pays a fair price in Melbourne at jewelleryvaluer.com.au
Had my private collection x-rayed there as well and didn't ask for a penny for the time; thats why I'm spruiking them a bit here-I was vey impressed for once.

cheers.

Rod