What is the cost of diamonds or diamonds with 1 carat?
The price of diamonds is defined by the 4C: Carat, Color, Clarity and Cut. The weight in carats is one of 4 factors
that are used to determine the value of a diamond, but without knowledge of the other three it is not very meaningful.
A concrete example: a brilliant with 1.00 carat, which is just in the "investment range", i.e. has a sufficiently high quality to be bought as an investment diamond, currently costs from about €5,000 (1 ct, color G, clarity VS1, cut VG, certificate GIA, without fluorescence). A diamond of 1 carat weight, also certified by GIA, in highest quality (1 ct, color D, clarity FL/IF, cut 3EX, without fluorescence) is already at least €13,000, in each case calculated without VAT.
The price differences are even more extreme if diamonds that do not have investment quality are also used as a comparison. Thus, 1 carat diamonds with strongly visible inclusions, which are clearly visible to the naked eye (I2-3/P2-3), a stronger yellow tint (K-Z) and only a good cut, are traded for a few hundred euros.
The question "What does a carat of diamond cost?" cannot be answered in a simple way. If you want to compare the prices of diamonds from different suppliers, you should always choose stones as a basis which have exactly the same 4C if possible. Only then is the comparison representative.
The shape of the cut also plays a role in the selling price, regardless of its quality. Round brilliant diamonds are always slightly more expensive than more exotic cut shapes, all other things being equal. Not because a different cut shape is worse or less beautiful per se, the demand is simply much higher for brilliant diamonds than for square shapes, for example.