What is a carat? Essential information on gems and jewellery

The weight of carats of diamond and precious stone is crucial for the pricing of the gem. Before buying the gems and jewellery, know what a carat is and care about your purchase.
Although many people think of a carat (ct) as a measure of the size of the gemstone or diamond, a carat is not a particular format. It is, in fact, a specific measure of metric weight. Moreover, the carat is different from karat (kt), which is a measure of the United States for the purity of gold.
The carat is a primary measure of the gem and diamond industry because in just about every level of transaction and trade often with the exception of the retail sales of consumer end diamonds and gemstones are sold by their weight carats. Buyers of common sense knows the current values ​​of special stones and understand how to negotiate further, where to buy loose stones, antique jewellery from new or second-hand jewellery. 

History of the measure in carats of the gem trade 

 
Since ancient times, the standard weight used for gems in the gem trade has been the gold. In the new international diamond carat of 200 milligrams, Transactions of the American Institute of Mining Engineers, volume 47, 1914, the gem expert George Frederick Kunz writes that before the year 1913, the carat weight in different country to country. The early gem traders around the world have used or very small and relatively uniform grain to measure small items such as precious and precious stones. Many traders and grain planted specifically to be collected and used as a measure of weight. The seeds of wheat and carob were particularly notable as the unit of measure for weight.

According to the Gemmological Institute of America, today's modern pearl grain, wheat and grains troy pharmacists and AV they all descended from the grain of wheat. Moreover, the modern metric carat has evolved from an ancient carob seed.
Even if the barrels were relatively universal term, the exact weight of a carat was not. Around the world, these ancient, and several grains in size and weight that make unequal measure carats from one place to another. For example, according to Encyclopaedia Britannica, while the carats of London were equal to 3.168 grains troy, or 0.2053 grams, while the carat of Florence was 0.1972 grams and carats of Amsterdam were 0.2057 grams.
Also, in earlier times, the weight of a carat was calculated from the integers carats more fractions (1/2, 1/4, 1/8. 1/32. Or 1/64) of a carat. In general, this practice continues today. However, the actual weights of loose diamonds and precious stones are calculated quite precisely.
Standard weight of carat for gems
In 1913, led by French measures Conférence Générale, for an international concern of weights and measures, many countries around the world came together and agreed to define the metric carat as a unit of weight is equal to 1/5 of a gram, or 200 milligrams. This is the measure used in industry today and gemstone jewellery, according to the International measures office, the board of directors responsible for the International Conference.

How to choose diamond jewellery

Since the fractions of a carat can represent hundreds or even thousands of dollars, diamonds are measured by thousandths of a carat and rounded to the nearest hundredth, or point. There are 100 points to a carat. Thus, for example, a stone of half-carat is 50 points. In the U.S., the Federal Trade Commission strictly regulates how the jewellery industry is the weight of the gemstone.
When buying jewellery featuring more than a diamond or precious stone, be aware of the difference between the coach, which means the carat (singular), the cts (plural) and a stone as soon as the central or primary of CTW, which stands for carat amounted to the weight and refers to the total weight of all the stones together, in a part. 

Old diamonds may weigh more 

An important note for buyers of antique gems: in the beginning, a carat might actually weigh more than the modern metric carats. Be on the lookout for this if you are shopping for antique jewellery or gems, particularly those offered for sale which may include original reports or certificates of sale. For example, an old European cut diamond in an antique ring provided with the original receipt (which specifies the diamond as a 1. 50 cents), will most likely be larger than 1. 50 cents by today's standards.
Moreover, the only way to accurately assign a weight to a diamond or a precious stone is weighing the loose stone, using proper equipment before it is set in jewellery. So, unless a jeweller unset and recovered a precious stone in a part of jewellery (a piece of property or particularly second-hand), or there is a certificate that accompanied the loose stone before it was set in jewellery, the weight specified by a set of precious stone in jewellery should be considered an estimate.
As the weight of carats hits the pricing of the gemstone and diamond
As stated earlier, the carat weight is important in industry because of the gem and diamond gemstones are priced and sold by the weight of their per-carat. Put simply, the finest and most limited the precious stone, the higher the price-per-carat. For this purpose, as a gem increases in size, price-per-carat increases usually because in most cases, the larger, the stones of gem-quality are more rare smaller stones. 

Also, most varieties of the gem, the escalation in the price per-carat does not increase in direct relation to the increase in size. Usually, the price increases are much greater than the corresponding increases in the size of the gem. For example, although two-times the size of the weight of 2 ct diamond will be well-more than twice the price of 1 ct diamond. In fact, a larger gem can be three, or ten times more expensive than many other smaller stone of similar quality. A 3 ct diamond will be even more disproportionate in price is that 2 to 1 ct stones.
Size of diamond versus weight: Looking up and diffusion can mask the true weight
Currently, there is an impression dell' standard-sizing for diamonds, meaning that many people think that all the diamonds of 1 ct have the same measures. Not true. As mentioned earlier, there is no particular format that relates to the particular weight of the gemstone.
When referring to the size of the gemstone and diamond, you're usually referring to the format of the profile of the belt. The format of the profile of the belt is sometimes referred to as the spread or the format facing up. 

The misconception that all the diamonds of 1 ct are the same format, for example, is partially supported by the introduction of aggressive marketing of the diamond industry and the consumer preference for round brilliant cut diamonds of a style particular (mainly diamond engagement rings). Thus, although it may be safe to use, say, 6. 5mm, as a measure of the average benchmark for an average - ct round brilliant diamond, this is only an estimate in terms of size. A 1 diamond ct that is more shallow cut, the larger facing upwards, to mean the diameter of the belt will be greater and, perhaps, when viewed from above, the diamond will appear to be up to 1. 25 cts. The deeper cut 1 ct stone will show a smaller spread and can not look great as its official weight of 1 ct. 

Consider the format facing upward as well as weight
 

Compared to the diamond-shaped and round brilliant faceted styles, size for the diamond cutting work including pear, marquise, radiant point, the princess, emerald cut and the point, as well as others is more difficult to generalize in terms of expected format. For this reason, it is often more useful to buy a format upwards particular in millimetres, that is to purchase for a specific weight of carats. Moreover, given facet model, such as cutting the square of the princess, for example, are known to be slightly more deep, so their size upwards will generally be smaller similarly around the brilliant cut.
Knowing that many beautifully cuts, larger upwards on smaller diamonds of their expected format, can lead to a happy advantage of prices for an astute buyer. 

One final note, because the precious stones have different mineral compositions, their density or specific gravity, is not the same. Thus, different types of precious stones usually have different weights of carats when their formats facing upwards of a millimetre may be similar.
For example, the specific weight for the diamond is 3.5 and the specific weight for corundum, or sapphire, is 3.9-4.1. The sapphire is heavier than the diamond, so a 1 ct sapphire will be smaller in size than the same-ct diamond weight 1. In contrast, the specific weight for the emerald is 2.6, making for a 1 ct emerald gem of the largest of the three jewels of 1 ct.