In other words, 18 karat gold is different from gold in every way,
just as 9 karat gold is.
If you go to the very beginning of this subject, you should see that
I said that alloy is starting to exhibit some properties of gold when
at least half of it's atoms are gold. I also emphasized that not all
the properties but some!
For jewellery work mechanical properties of gold, which we are
loosing by alloying it, are not desirable anyway. What we want are
color, reflectivity and resistance to corrosion. And these only begin
to resemble gold when at least half of the atoms are gold. Properly
formulated 18k satisfies the requirement, anything less does not !
And if you want to understand how important the color is, - here is
the subject to research.
Why paintings are always framed in gold ? You can go to any museum to
verify this. Because color of gold improves saturation of other
NO OTHER COLOR HAS THIS PROPERTY !
And saturation is a lot of money in jewellery. Just price some
gemstones like emeralds graded 3 versus 4, in GIA nomenclature.
That is why colored gemstones must be only mounted in 18k yellow
It is extreme silliness to mount them in anything less. The apparent
loss of value is far exceeds "savings" of using lesser alloys. And
for me, the most remarkable thing that I learnt from this discussion,
is that some jewelers, claiming a lot of experience, are completely
unaware of this simple fact. The most important commandment in
goldsmith's bible is never to suppress appearance of a gemstone.