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Differing colors of 18k gold


#1

What accounts for the differing color I see between 18k gold wire
from CGM or Rio and the same gauge wire from India? The Indian wire
is much warmer, yellower, and seems to have a less brittle "hand,"
while the American wire looks and handles like 14k. Anyone know?

Thanks, Barbara
Barbara Lee
Gemella Contemporary Jewelry
www.gemella.biz
www.gemellajewelry.etsy.com


#2
What accounts for the differing color I see between 18k gold wire
from CGM or Rio and the same gauge wire from India? The Indian
wire is much warmer, yellower, and seems to have a less brittle
"hand," while the American wire looks and handles like 14k. Anyone
know? 

The karat content of course tells you only how much gold is in the
alloy. The rest can be very variable. There is no one single formula
for yellow gold, for example. Classically, it’s some mix of copper
and silver. More copper is more a rose gold. All copper is a very
rose/red color. More silver gets paler, and the alloy gets softer
too. All silver is very pale, sometimes called green gold (though a
greener tinged yellow comes if you add cadmium too.)

But any given supplier will likely sell several variations of yellow
gold alloys, and a similar color from a different supplier might be
slightly different in the copper to silver ratio.

And this is just the copper and silver. Many alloys used also
incorporate small additions, like zinc or silicon as deoxidisers, if
the alloy is supposed to be useful for casting as well, and even when
alloys are developed and sold first as casting alloys, you may be
ordering wire in a similar alloy, just so colors match between the
casting alloy and wire that may be part of the same jewelry piece.
If you then order wire, say, from india, that doesn’t happen to have
those deoxidisers, then the color is often a bit richer, and may work
differently.

And finally, are you comparing the same degrees of hardness? Perhaps
the wire from india is fully annealed, while the wire you bought from
Rio or others was half hard. Makes an enormous difference. Due to
depletion gilding effects from how it was last annealed, the color of
the annealed wire may also be a bit richer as a surface coloring.

Peter


#3
What accounts for the differing color I see between 18k gold wire
from CGM or Rio and the same gauge wire from India? 

probably differing base metals that are being used in the production
of the gold alloys.

john


#4

all manufacturers have a proprietary formulation of karated
products. generally the less zinc the richer the colour. Silica is
generally colourless and doesn’t add nor detract from that rich
ancient yellow colour you see in Indian jewelry. the amount of copper
used has bearing on the colour as well as does the zinc. In foreign
made mill products there are genrally less deoxidants and additives-
primarily they use fine gold, copper and silver to achieve differnt
Karats of yellow golds… rer