Diamond is weighed on a diamond scale and priced by its carat weight. There are 100 points to a carat. A one carat diamond weighs about 1/5th of a gram. All other factors being equal, as carat weight increases, cost increases exponentially rather than geometrically. Example: A 2 carats diamond is over 3 times the cost of a 1 carat diamond, even though it weighs only twice as much. Why? Polished diamonds are cut from rough diamond crystals, referred to simply as “rough.” About half the weight of the rough is lost in the cutting of the polished stone. A 4 carats piece of rough, which cuts into a 2 carats polished diamond, is more than 3 times rarer in nature than a 2 carats piece of rough, which is cut into a 1 carat diamond.

At various times, with various shapes, there are advantageous “price breaks” at certain carat weights. Example: A diamond weighing .90 carat, which cannot be distinguished from a full 1.00 carats diamond, may be 20% less expensive. Why? Because the rough that weighed 1.80 carats, which was cut into the .90 carat polished diamond costs about 20% less than the 2 carats rough that was cut into the polished 1 carat diamond. Clients interested in the best value for their dollars should ask jewelers about these price breaks, assuming the seller does not offer the information outright. The billions of dollars spent worldwide to convince the public to purchase diamonds which weigh more sometimes creates a psychological block that prevents the client from examining diamonds of very slightly lesser weighs, even if those stones would save the client lots of dollars.

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