in
the same period. It is generally found in the sand of placer mines and
the usual yield is one ounce of platinum to a ton of sand.
For
use it must be alloyed with iridium and when properly alloyed is very
hard and retains a fine brilliant finish. As iridium is far more
expensive even than platinum, some manufacturers, in order to secure
platinum at lower price, have not used enough iridium in their alloy,
which has resulted in the metal becoming soft and turning dull or leady
in color. Platinum of standard hardness of alloy weighs nearly sixty
per cent more than fourteen-carat gold, and while fourteen-carat gold
costs sixty-four cents per pennyweight, platinum now costs about $2.50
per pennyweight.
In
computing as an example the value of a diamond mounting, it might be
said that a diamond mounting weighing ten pennyweights would cost for
the gold $6.40; a mounting of the same size in platinum would weigh
nearly sixteen pennyweight and cost nearly #40 for the material.
The
cost of working platinum is also far greater than that of gold, but its
brilliant finish and hardness and harmonizing color make it far the
best metal for fine diamond and pearl mountings.
