In the jewellery industry, gold, platinum and silver are known to be precious metals. Technically, the term precious metals refers to metals that are stable in air and not subject to oxidation. This is strictly true of gold and platinum. Silver, though tarnished when exposed to sulfur, is included because of its widespread use in jewellery.
In it’s pure form, gold is a shiny yellow metal. It is soft and easy to work with. With a specific gravity of 19.4, it is one of the heaviest of the common metals.
Platinum is a metal with a naturally white colour, where white gold is specifically an alloyed metal.