Gold, silver, and platinum.
And palladium, iridium, rhodium, platinum, ruthenium, rheniumosmium
Because they are rare metals or uncommon metals
gold
Gold, silver, and platinum have been called "precious metals" because they are metals and were used to make coins (money) in the days when money had to be made of something that was considered to be...
because it is used in all kinds of things such as wedding rings and watches