What are precious metals?
Precious metals are metals that do not form oxides or do not do so easily (that is, they do not form chemical compounds with oxygen and other gases (and thus do not rust)).
They include: ruthenium, rhodium, palladium, silver, osmium, iridium, platinum and gold.
What are non-ferrous metals?
Non-ferrous means that there is no appreciable amount of iron present.
All metals and alloys that do not contain iron can be described as non-ferrous.
What are heavy metals?
In contrast to light metals, heavy metals are metals with a specific weight of more than 4.5 g/cm3.
What is one carat of gold equivalent to?
The term "carat" originates from the dried seeds of the Carob tree, which were used in olden times in Eastern India and Mediterranean countries for weighing diamonds and gold. The weight of these seeds is very consistent (0.2 g). To be able to specify the pure gold content of gold alloys in terms of carat, it has been usual practice since medieval times to use the "Cologne Mark" as a basis. In the case of gold, this mark could be divided into 24 parts. This is why the figure of 24 carat was laid down in those days for pure gold. 1 carat is therefore 1/24 the weight or 4.1666%. The 21.6 ct alloy with 900/1000 gold content is also often used. This alloy can primarily be found in coins and Oriental jewellery.