Frequently asked questions


1)    Is there any parallel between carat of gold and carat of precious stone?


No, it is just a rather unfortunate case of coinciding denominations. When talking about gold, carat represents a ratio of gold included in an alloy; i.e., pure gold is designated as 24 carat gold. The less pure the gold is, the lower the number of carats used to designate gold. For jewelry purposes, typically 18 or 14 carat gold is used.  18 carat gold (also designated 750, as in 750 units of gold in 1000 units of alloy) contains 75% of gold in the alloy, while 14 carat gold (also designated as 585) contains 58.5% of gold in the alloy. Some jewelers abroad also use low cost 8 carat gold (designated as 333), which only contains one third of gold in the alloy. The jewelry made from this gold is very cheap, but of lower quality and is more likely to cause allergic reactions, due to higher presence of nickel or copper in the alloy.

When talking about precious stones, a carat represents a unit of weight. This denomination originates from Arabian marketplaces, where carob seeds were used to weigh stones as they were of very similar weight. The word carat came from Italian carato, which came from Greek kerátion (κεράτιον) meaning carob seed (literally "small horn" – which is the shape of carob).  1 carat represents a weight of 0.2 grams, therefore 5 carat stone weighs one gram.

2)    What is the difference between diamond and brilliant?

Diamond is a natural mineral, the resource, which is further refined. Brilliant is a type of diamond cut. In its round form, it is the shape, which most people think of when they hear about diamonds. It should be noted that despite what most people think, brilliant cut is not necessarily round, for example, pear shape, heart shape or marquise are also brilliant cuts. Each of these shapes has specifically defined parameters. Round brilliant cut consists of small, precisely cut facets – it contains 57 of them (58 if the culet is faceted). This cut takes full advantage of optical properties of a diamond. Ideally cut diamond reflects up to 99% of light. For this reason, such stone has most “life” and comes with the highest price tag of all the traditional cuts and shapes.

3)    Why are there different colors of gold?

The color of gold is determined by amount and type of elements in the alloy. For instance, white gold is an alloy of gold, nickel and palladium, rose gold contains copper. Other typical elements used in gold alloys are silver and rhodium. As 24 carat gold is 99% pure gold, it only comes in yellow color.

4)    Is 1 carat diamond two times as large as 0.5 carat one?

One carat diamond in round brilliant cut has a typical average diameter of 6.5 mm and height of 3.9 mm. Half carat diamond has average diameter of 5.2 mm and height of 3.1mm. This shows us that diamond, which is twice as heavy, is only slightly larger. The easiest thing to do is to remember, that 0.1 carat stone has 3 mm in diameter and 1 carat has 6.5 mm in diameter, everything else is “in between”. These measurements are easy to estimate on the first glance and it will not make you feel like an absolute layperson while briefly examining a stone.

It is not twice the price either. In fact, one carat stone is much more expensive than half carat one. To give you an example, Rapaport price of 0.5 D IF stone (July 2014) is 8,700 USD per carat (4,350 USD for 0.50 D IF stone then), the same color combination in 1 carat equals 27,500 USD per carat. That is more than 6 times more expensive!

5)    Is it possible to determine the parameters of a diamond set in a piece of jewelry?

An expert is able to determine the approximate parameters even if the diamond is set, with a decent degree of accuracy. Weight can be calculated using measurements of the stone (that is, if they can be measured, some settings limit this possibility), clarity can be determined even though jewelers try to hide the inclusions with gold – this might prove to be easy or very difficult, depending on the setting. Color is generally harder to determine, as it is influenced by color of metal. An objective grader usually leaves a small leeway, as he might do with clarity.

Respectable businesses, selling diamond jewelry, provide a grade certificate to both stone and jewelry. The stone should be graded before it is set to ensure the accuracy of the grade.

An experienced jeweler can uplift the advantages of used stone and, conversely, hide the minor imperfections the stone might contain, thus forming a unity of stone and setting.

DIC JEWELLERY All you need to know about diamond jewellery