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Minimum standard of quality gold


#1

Was: Stablized tourquise health hazard

Now 18 karat gold is 750 parts of gold for 1000 parts of metal, and
is the international minimum standard of quality gold in the
WESTERN world. 
Is that a pseudo standard, although I sort of agree, I can't say
I've read it anywhere. 

An interesting question - which gold is gold and which gold is crap?

We need to delve into a bit of science to dig out the answer. For a
gold alloy to have at least some properties of gold, - gold must be
dominant component in alloy, at least 50% of atoms must be gold. The
questions is how to determine that without actually counting atom one
by one, because it is kind of tedious. Analytical chemistry to the
rescue.

First let’s recall Avogadro number, which is 6.023E+23. This is a
really big number and those who unfamiliar with scientific notation,
think of it as number of dollars that even US government cannot
spent, no matter how hard they try. Avogadro number represents
number of atoms in one mole of substance. This number is the same for
any chemical entity. Sometimes it is called Avogadro Constant. So if
we take one mole of gold and one mole of silver, such alloy would
have numerically 50% of gold atoms and would satisfy criterion of
gold which is gold.

One mole ( one mole of element in grams is equal to atomic weight of
that element ) of gold weighs 197 grams and one mole of silver weighs
108 grams, which yields 64.6% by weight or 15.5k, Here goes 14k
standard, but story is even more interesting. Consider one mole of
gold and one mole of copper. Mole of gold is 197 grams, but mole of
copper is only 64 grams. So in this case minimum purity is 75.5% or
slightly above 18k. That is why 18k alloys always have some silver
present.

I do not want to drive everybody crazy with endless calculations,
but think what happens when we introduce zinc, or other metals in
alloys. By doing that, the number of gold atoms becomes less than
50%, and the gold becomes crap. That should also answer the question
about difficulty of wearing rose gold, which was posted. Also
consider how dumb the standard of 14k is. Composed traditionally of
gold, copper, silver, and some zinc ( casting alloy ), it definitely
is the gold, which is truly crap. And to add insult to injury, there
are alloys with silicon and etc. Frankly, I am amazed that people do
not loose their fingers, wearing the stuff. And 9k!. don’t even get
me started!

Leonid Surpin
www.studioarete.com


#2
An interesting question - which gold is gold and which gold is
crap? 

Well I think practically which gold is gold is determined by the
country where you live.

Here in Australia, gold is anything greater than 9k, but in America
10k is the minimum.

As far as pain in the ass value goes 9k is a pain to work with
especially if it’s 9k red :frowning:

Regards Charles A.


#3

Leonid- I have a friend, who has a PhD in Chemistry. he actually
named his daughter Avagadra, which in his mind is the feminine form
of Avogadro. Unsurprisingly, she goes by Ava.


#4
I do not want to drive everybody crazy with endless calculations,
but think what happens when we introduce zinc, or other metals in
alloys. By doing that, the number of gold atoms becomes less than
50%, and the gold becomes crap. 

You make an interesting argument, but the momentum of our culture,
legal standards and the fickle values of fashion are a lot to
overcome. It seems highly unlikely that an 18K+ standard is going to
catch on in the West.

Don’t get me wrong. I personally prefer the rich, buttery color and
luster of higher karats, but my customers usually prefer the more
familiar color of 14K yellow and don’t see paying more for a softer,
less durable material for the snob-appeal of a higher karat. At the
present, white alloys are far more fashionable anyways.

I have a strict policy in my shop, never to call anybody’s jewelry
"crap", even when it clearly is inferior stuff. We are dealing with
a very emotional product with jewelry. Your argument makes a lot of
sense in terms of appreciation for gold, but to insult most of what
our customers already have and love does not seem like good
salesmanship. You have given me a good argument that I think will be
very useful to sell higher karats but I think the sales pitch will
work just as well without heaping disdain on the alternatives.

Stephen Walker


#5

Isnt it funny that 9ct claws are a pain because they are too hard
and 18ct a pain because they are too malleable? I must confess a
dislike to 9ct casting alloys as they always seem to have an odd
colour to them and take more effort to polish. I prefer 18ct but then
become wary of doing anything exciting because of cost. Still, at
least I get to choose.

Nick Royall