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How to determine purity in metals?


Hi All,

I was wondering how the Cash for Gold and refiners are determining
purity in scrap. Are they using acid testing, zapping it with a
handheld thingy? With all this refining going on, how are they doing
this so quickly? I’m seeing people at malls now who are taking in
the gold scrap and then literally writing checks. Somebody asked me
about going to a gold scrap party. You bring your metal, they weigh
it and give you cash on the spot.

Karen Christians


some are professional metal testers (i like ones that give a read out
of all the components of the piece of metal placed on the gun’s
platen- they told me the ring stamped Pt 10% iridium was actually
composed of 60% palladium, 10 % Ir and the balance Pt) thry have
integrated software run about $1,500 are hand held. Most use cheesy
150-2 hundred dollar ebay gel testing guns, or worse the battery
operated metal purity indicators that dont use acid but measure
density and read the pre set karats. i placed a sample of 20 karat
gold on it intentionally as a test: it read 18 kt instead of the
higher 22 karat which was more appropriate given the gold content
was above 750 gold and are far less reliable, then there aare some
dealers that use acid testing and needles. but the real telling thing
about these gold buying tv ads is this- I called the cash4gold number
posted on the tele and a man answered I assked him what % OF spot
they pay on gold. not only did he have no idea what it was (he
admitted!! but after asking someone in the next phone center cubicle
he said maybe 20 percent but neither of them knew for sure! And with
their current 25% extra cash promo they mean an extra 25% of the
payout…that is on 24 karat gold and it is lower as the karat

And then there are the scales in use! I have seen some differ as mch
as 6 dwts in digital scales that are used as they come out of the
box with a couple of “AA” batteries and no calibration For instance,
and because today i sold some locally to an honest metals buying coin
dealing guy who is using the reallY good equipment: I had over 16 oz
of fine silver scrap, and one british soverign ( from the victorian
period), parts of that Pt /Ir ring setting and 19 dwt. s of 18 kt
gold @ $38. 00 for 18 karat got a t otal of $1560. 79 THE CASH 4 GOLD
"offer" was $604. 00 before the extra 25%. (though over the phone,
not sending it to them).

A roughly 2/3rds more locally from an honest business than a TV rip
off. Occassionally I buy clients gold scrap at an average of $30. 00
a dwt. if it’s stamped and/or verifiable high karat gold. or coinage
and then the refinery i deal with pays me an avrg. of 98 % of
spot…that is about 4- 5 x’s more than i paid out. I get a discount
on new casting grain (essentially the only thing i buy from metals
vendors is 24 kt grain and .999 silver - from that I can make any
alloy in any colour i need without dealing with problems resulting
from trying to recycle scrap). This way I give the customer more than
the TV ads, or pawn shops or “buying parties”, and I make money and
new raw materials.

Buying parties are a bad way to go unless you know jewelry and metals
well including international markings and standards and have some
knowledge of historical markings too as about 50% or more of what I
get from clients is from the 18th-19th centuries before international
standardization in fineness and markings. You also never know if the
metal has been adulterated- I know of a local coin dealer that
accepted an ingot the client said he melted and poured himself, that
was 5 oz. s total weight but was sterling on the inside of the ingot
and the outer 30 mm was 18 karat gold. When put on his tester the
contact plate read 18 karat when in truth it was far less than 1 oz
of fine gold relative to the whole ingot- if you don’t know the
people you are dealing with, where they got their gold scrap,
etc…then it’s not only risky but illegal to buy and sell precious
metals in that fashion - unless expressly between friends, but there
are many fine lines to consider when announcing the parties,
exchanging cash and recourse if you have been defrauded.


R.E.Rourke wrote…

i placed a sample of 20 karat gold on it intentionally as a test:
it read 18 kt instead of the higher 22 karat which was more
appropriate given the gold content was above 750 gold

Why should 22kt be more appropriate? If it read 22kt it would be
just as wrong as reading 18kt but it would also be illegal as you
can’t claim for gold that isn’t there…! In the UK any piece
submitted for hallmarking with between 18 and 22kts will be
hallmarked as 18kt even if it is 21.98kts - that is the law here…

Ian W. Wright
Sheffield UK