Karat is a traditional unit of
measure based on the
Carob
seed of the Middle East.
Thus 24 Carob seeds should weigh
the same as 1 oz of Pure Gold in the old world.
2
Julius Scaliger in 1735 Italy isolated
Platinum. It's name platina (little silver) is Spanish due
to the conquistadors panning for gold in the rivers of Central and
Southern America. They would find heavier than normal white
nuggets of metal. They considered them to be undeveloped silver
and would throw them back into the water, till they could melt it.
Platinum melts at a higher temperature than Steel 1772°C
3222°F
3
Gold
Melts at 1064.58°C
1948.24°F
Silver melts at 961°C
1762°F
The development of white gold only
occurred about 125 years ago. The alloy itself is called German Silver,
Mock Platinum or White Brass, and is an alloy of 50 per cent copper, 30
per cent zinc and 20 per cent nickel.
Thus 6 parts German Silver plus 18 Parts Pure Gold will make
18 Karat White Gold.