What is a Troy Ounce?
Gold, silver, platinum and other precious metals are traditionally weighed and traded in troy ounces. Nowadays metric units are also used, but troy measure continues to be used extensively, and there are no signs that it will be replaced by the metric system in the near future.

31.1035 Grams
A troy ounce contains 31.1035 grams.
There are 1000/31.1035 = 32.15072 troy ounces in a kilogramme.
12 troy ounces = 1 troy pound.

Weight