Diamond Carat
Diamond carat has the biggest influence on final diamond price. The diamond carat means the actual diamond weight. Diamond weight is also the main indicator for how exceptional and rare a diamond really is. Bigger the carat - rarer the diamond.
Diamond carat defines only the diamond weight and not the diamond shape or diamond dimensions. The diamond carat can have an effect on diamond shape, but diamond shape is not dependent only on diamond carat. Sometimes it might depend on how each Jeweler cuts the diamond.
A jeweler can sometimes make the diamond look bigger than it actually is by increasing diamond diameter and decreasing the diamond depth. The diamond carat is used only and exclusively to describe the actual diamond weight.
Finding the carat weight for round cut diamonds is fairly easy. It can be determined by measuring the diamond depth and diamond diameter. If the diamond has other diamond shape it is harder to estimate the diamond carat.
Also the diamond price rises exponential with the diamond carat because the heavier diamond is much more rarer and more expensive.
For example if the price for a 1 carat is 8000 USD per carat, the price for 2 carat diamond would not be 8000 USD per carat. Actually it will be higher for example somewhere from 10000 USD or more. So the whole price would not be 16000 USD for a 2 carat diamond, it would be 20000 USD, (10000 USD per carat).
For example 3 carat diamond would have even higher price per carat. It might be somewhere from 15000 USD per carat. So the final price for that 3 carat diamond would be 45000 USD.
So our advice is that if you are looking for more than 1 carat diamond, you could consider buying a diamond with more stones so the price per diamond carat would be lower.