What is a stone?
A stone is 14 pounds, or about 6.35 kilograms, and the United Kingdom and Ireland use it almost entirely for body weight. Elsewhere people use kilograms or pounds.
We provide a calculator on this site to convert stones to kilograms.
What are Troy Ounces?
A troy ounce is the unit gold, silver and platinum prices are quoted in. It is about 10% heavier than an avoirdupois ounce, but a troy pound has only 12 of them.
One troy ounce is equivalent to approximately 31.1035 grams, which is about 10% heavier than a standard avoirdupois ounce. The term "troy" originates from the city of Troyes in France, where this unit of measurement was historically used in the trade of precious metals.