Gold-, Silver- and Platinum-alloys

Why Gold, Silver und Platinum can´t be worked up pure

Gold, Silver und Platinum are very soft and ductile metals.
Therefore they are not often used for jewellery, because jewellery could very easily be destorted and junctions like lugs and hinges could rub through and even it´s polish would not last very long.
So silver, copper, zinc, tin, palladium and other metals are added and molden to alloys.
In this manner both the hardness and the stability of precious metals are increased.

Gold-alloys   Gold-alloys can have various colors, depending on the metals, that were added:
Yellow (Alloys with additions of silver and copper, using a mixing ratio of 1:1)
Red (Alloys with additions of more copper and less silver)
White (Alloys with an addition of palladium or nickel)

Standards of gold recognised in Austria (per mille):

986 parts gold per 1000
Used for gold-coins in former times, with an addition of copper only, color is similar to fine-gold.
900 parts gold per 1000
Alloy with silver and copper, is equal to 22 ct.
750 parts gold per 1000
Alloy with copper and silver, is equal to 18 ct.
585 parts gold per 1000
Alloy with copper and silver, is equal to 14 ct.

Austrian Standards of gold in carat
(1 carat = 1 ct = 1/24)
24 ct   24 of 24 parts are gold, equal to fine-gold.
22 ct   22 of 24 parts are gold, equal to 900.
18 ct   18 of 24 parts are gold, equal to 750.
14 ct   14 of 24 parts are gold, equal to 585.   Silver-alloys All standards with alloy addition of copper only.
925 parts silver per 1000
900 parts silver per 1000
835 parts silver per 1000
800 parts silver per 1000
   Platinum-alloys 950 parts platinum per 1000
This is the only standard for platinum in Austria. Platinum is used for fine jewellery-work and is alloyd with either palladium or copper, for parts with a maximum of hardness iridium is used.