If diamonds are valued by the 4 C's (cut, carat, clarity, color), what is the value of a diamond that is used in jewelry in an uncut state?

Before they are cut (and even after to be honest) the value is based on the amount of chemical impurities in the diamond. The more pure the diamond the higher the value. A type IIa (the purest type) accounts for less than 2% of all diamonds. They are also considerably harder than other types of diamond.

All diamonds are a scam. Really want to know how the diamond trade works? Read this.

oh, and let’s not forget this

Very very few people would market uncut stones that a sorter has deemed high quality. I won’t say it’s a scam but it is creative.

Good question. I don’t know. I just keep thinking of the phrase, “diamond in the rough.” I personally think, and I don’t have anything whatsoever to back it up, that the value comes in the cutting and polishing. I know there is a mathmatical formula developed in 1919 to cut the perfect diamond shape for the most sparkle.

You can be pretty certain that such diamonds are used in that state because cutting and polishing them would not produce a stone of any great economic value or aesthetic quality.