The carat (abbreviation ct or kt) is a measure of the purity of gold alloys, 24-carat being pure gold. The carat system is increasingly being complemented or superseded by the millesimal fineness system, in which the purity of precious metals is denoted by parts per thousand of pure metal in the alloy.
Where did such an unusual unit of purity come from?
The word carat is derived from the Greek kerátion (κεράτιoν), “fruit of the carob”. Carob seeds were used as weights on precision scales because of their reputation for having a uniform weight. (However, a 2006 study by Lindsay Turnbull and others found this not to be the case). This was not the only reason. It is said that, in order to keep regional buyers and sellers of gold honest, potential customers could retrieve their own carob seeds on their way to the market, to check the tolerances of the seeds used by the merchant. If this precaution was not taken, the potential customers would be at the mercy of “2 sets of carob seeds”. One set of “heavier” carob seeds would be used when buying from a customer (making the seller’s gold appear to be less). Another, lighter set of carob seeds would be used when the merchant wanted to sell to a customer.
In the distant past, different countries each had their own carat, roughly equivalent to a carob seed. In the mid-16th century, the Karat was adopted as a measure of gold purity. The most common carats used for gold in jewelry making are 9 and 10 carat in New Zealand.
The value of your gold is determined by three things – the weight, the carat and the current market price. Higher carats of jewellery contain more gold (e.g. 18ct has two times more gold than 9ct) and the heavier the total weight means more cash for you.
At Gold Smart you will receive the highest price for your gold and silver because we are transparent about the entire pricing process.
Original Source – http://en.wikipedia.org/