Welcome to Brainstuff from how stuff works dot com where smart Happens. Hi. I'm Marshall Brain with today's question, what is a carrot and what is the difference between a carrot spelled with a C that's used with diamonds and a carrot spelled with a K that's used with gold. A carrot spelled with a C is a unit of weight for diamonds and other gemstones. One carrot equals two
hundred milligrams, about a fifth of a gram. There are four hundred fifty three grams in a pound, so if you had a one pound diamond, it would be a two thousand, two hundred sixty carrot diamond. A carrot, when used with gold spelled with a K, is a unit of purity. Four carrot Gold is pure gold, but usually you mix gold with a metal like copper or silver when you make jewelry because pure gold is too soft and it's also really expensive. Each carrot indicates one four
of the whole. So if a piece of jewelry is made of metal that is eighteen parts gold and six parts copper, that's eighteen carrot gold. Where did such a funny unit of purity come from? It turns out that a German cold coin called a mark was common about a thousand years ago. It happened away twenty four carrots or four point eight grams. The purity of gold in the coin was expressed in the number of carrots of gold spelled with a C in this case present in
the twenty four carrot coin. So the two words carrot and carrot are actually related through this process about a thousand years old. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com.