What is a carat?
A metric carat is 200 milligrams (0.2 grams), the unit gemstones and pearls are weighed in. Karat with a K, which measures gold purity, is a different thing.
What are Troy Pounds?
A troy pound is about 373.24 grams, which makes it lighter than the avoirdupois pound of 453.59 grams. It was the pound of the precious metals trade, though gold and silver are now quoted per troy ounce.
One troy pound is equivalent to 12 troy ounces, which is lighter than the avoirdupois pound commonly used in everyday measurements. The troy pound is often denoted by the symbol "lb t" to distinguish it from the avoirdupois pound.