| Most gemstones are priced according to weight. | | | | value significantly. |
| The exceptions are some carvings and | | | | 4. Cut and Polish |
| cabochons, which may be sold by the piece | | | | Gemstones should be cut with proper proportions |
| rather than by the carat, since the work required | | | | to maximize the light that is returned to the eye. |
| to produce them exceeds the cost of the | | | | But gem cutters or often have to make |
| material. But for the vast majority of gemstones, | | | | compromises when cutting a particular stone. If |
| the price is computed on a per carat basis. One | | | | the gem color is quite light, cutting a deeper stone |
| gemstone carat is 200 mg, so there are 5 carats | | | | will provide a richer color. Conversely, a dark tone |
| in 1 gram. Don't confuse carat, a measure of | | | | can be lightened by making a shallower cut. But in |
| weight, with karat, a measure of gold purity. | | | | every case, the facets should meet cleanly and |
| The price per carat of different gemstones can | | | | the surface should be well polished with no |
| vary enormously, literally from $1 a carat to tens | | | | scratches. |
| of thousands. Many factors influence the price per | | | | 5. Size |
| carat. Here is a brief summary of the factors | | | | For some gemstone varieties, such as quartz, the |
| that determine gem prices: | | | | price per carat is fairly constant as the weight of |
| 1. Gem Variety | | | | the stone increases. But in the case of many |
| Some rare gemstone varieties -- such as | | | | rarer gems, price increases in a non-linear way as |
| sapphire, ruby, emerald, tsavorite garnet, | | | | the weight increases. Not only are larger stones |
| tanzanite, spinel and alexandrite -- command a | | | | much more expensive, but gems cut in stock |
| premium price in the market. Other varieties, such | | | | sizes -- what are known in the trade as calibrated |
| as many types of quartz, are abundant in many | | | | sizes -- also tend to be more expensive. This is |
| locations around the world, and prices are much | | | | because more material has to be removed to |
| lower. | | | | achieve the calibrated size. |
| 2. Color | | | | 6. Shape |
| In colored gemstones it is color that is the single | | | | Some shapes tend to be priced higher than |
| most important factor in determining value. Ideal | | | | others, in part because of demand and in part |
| colors vary by gem variety of course, but | | | | because of material issues in cutting the specific |
| generally the colors that are most highly regarded | | | | shape. In general, round gems tend to command |
| are intense, vivid and pure. Gems that are too | | | | a premium in the market. Rounds are much less |
| light or too dark are usually less expensive than | | | | common than ovals, since ovals are usually cut to |
| those of medium tone. | | | | preserve as much weight of the raw material as |
| 3. Clarity | | | | possible. Cutting a round gem normally requires a |
| A gemstone that is perfectly clean, with no visible | | | | greater loss of the rough stone, and for very |
| inclusions, will be priced higher. In general, the | | | | expensive materials like sapphire, ruby, alexandrite |
| cleaner the stone, the better it's brilliance. | | | | and others, this can have a significant effect on |
| However, inclusions that don't interfere with the | | | | price. |
| brilliance and sparkle of a gem will not affect its | | | | |