Rosa's heart was racing from the four cups of coffee she had just finished, but she thought she might be having a heart attack.
A carat is a unit of weight for diamonds and other gemstones. One carat equals 200 milligrams (0.200 grams). There are 453 grams in a pound (1,000 grams to a kilogram). Therefore, if your fiancee weighs 170 pounds, you have a 385,050-carat fiancee! A karat, when used with gold, is a unit of purity-- 24-karat gold is pure gold, but usually you mix gold with a metal like copper or silver to make jewelry (because pure gold is too soft). Each karat indicates 1/24th of the whole.
Pure gold equals 24 karats, or 24k, a caratage that can also be expressed in decimal form as .999 fine. Gold can never be 100% pure since there are always some impurities in it. The finest gold ever created was .999999 fine. The decimal is found by dividing the actual caratage by 24, the most carats gold can have.