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 pennyweights?
Pennyweights are a unit of measurement commonly used in the jewelry industry to measure the weight of precious metals such as gold and silver.
A pennyweight is 1/20th of a troy ounce, which is 1.55517 grams. Jewelers still use it for small amounts of gold and silver.
To get grams from pennyweights multiply by 1.555 – 10 pennyweights is about 15.55g. The abbreviation dwt comes from d for denarius, the old penny.