Diamond Carat Weight

Based on carats, the measure of a diamond's weight, you can't always tell the diamond's size. However, carats affect the way diamonds are priced, and the number changes exponentially. In this piece we've explained the difference 0.1 carats can make.


Diamond Carat Weight

The weight of a diamond is referred to in terms of carats. One carat equals 200 milligrams (0.20 grams) and is divided into 100 points for precision. A diamond weighing one tenth of a carat may be referred to as 0.10 carats or “10-points”.

A diamond’s carat weight is not necessarily reflective of its size. Two diamonds of the same carat weight may appear slightly different in size when viewed from above.

When evaluating the size of a diamond, the top diameter and cut grade must also be taken into account. The distance across the top of the diamond is crucial, as this is how diamonds are generally viewed once set in jewelry. The cut similarly affects perceived size. A well-proportioned diamond maximizes light, making it appear larger.

Diamond prices tend to jump by half-carats. You will find that the price difference between a 0.9 and 1.0 carat diamond is much larger the difference between a 0.8 and 0.9 carat diamond. Furthermore, diamond prices increase exponentially, rather than linearly. The scarcity of large gem-quality rough diamonds means that a single two carat diamond will cost much more than two one carat diamonds.

TIP: “Carat” (abbreviated ct) is not the same as “karat” (abbreviated K or kt). Carat is measure of gemstone weight while karat is a measure of gold purity.


There are a lot of factors to take into account which will determine the value of a 1 carat diamond, including the cut, clarity, colour and shape of the stone. Prices currently vary from anything from $1,800 to in excess of $12,000.
A single carat is 0.2 grams, and a 1-carat diamond will normally have a diameter of approximately 6.5mm. The size of a diamond’s diameter does not increase proportionately with the number of carats.
Prices for half-carat diamonds start at approximately $700 and can rise massively depending on the cut, colour and clarity of the diamond. The most you be likely to pay for the stone alone is about $2,000.
Engagement rings vary enormously in cost, so it is impossible to put a figure on them. There are several experts who believe that the man should spend two month’s salary on an engagement ring, while others argue it should be just a month. Probably the best option is to choose a ring that you and your partner will cherish forever.
Most insurance companies will insure engagement rings. However, as they have far more worth than merely monetary value, accurately putting a price on the ring can be a bone of conjecture. Some insurers say that the current market value plus twenty-five per cent is accurate, while others say significantly higher, or frustratingly lower.
The Hope diamond was removed from its setting in 1974 and was found to weigh 45.52 carats, significantly more than the 44.5 carats which it was previously valued at. It is known as an llb diamond and is semi-conductive and phosphoresce.