Carat is equal to 0.2 grams, usually abbreviated as "ct". Kela in Greek comes from "keration", which means carob tree. This is a plant that spreads widely from East Asia to the Middle East. Because it is said that its fruit weight is almost the same, carob is used as a unit of weight for jewelry and precious metals.

Weight unit of gemstone: carat (symbol: CT) 1 carat = 0.2g (200mg).