Rough tourmaline*** WARNING **** THIS PRODUCT IS NOT AVAILABLE ANYMORE ***** OPGELET **** DIT PRODUKT IS NET MEER LEVERBAARAfrican rough tourmaline perfect for cutting. Bought from special source. The price per carat of different gemstones can vary enormously, literally from $1 a carat to tens of thousands. Many factors influence the price per carat. Here is a brief summary of the factors that determine gem prices:
1. Gem Variety
Some rare gemstone varieties - such as sapphire, ruby, emerald, tsavorite garnet, tanzanite, spinel and alexandrite - command a premium price in the market. Other varieties, such as many types of quartz, are abundant in many locations around the world, and prices are much lower.
In colored gemstones it is color that is the single most important factor in determining value. Ideal colors vary by gem variety of course, but generally the colors that are most highly regarded are intense, vivid and pure. Gems that are too light or too dark are usually less expensive than those of medium tone.
A gemstone that is perfectly clean, with no visible inclusions, will be priced higher. In general, the cleaner the stone, the better it's brilliance. However, inclusions that don't interfere with the brilliance and sparkle of a gem will not affect its value significantly.
4. Cut and Polish
Gemstones should be cut with proper proportions to maximize the light that is returned to the eye. But gem cutters often have to make compromises when cutting a particular stone. If the gem color is quite light, cutting deeper, the stone will provide a richer color. Conversely, a dark tone can be lightened by making a shallower cut. But in every case, the facets should meet cleanly and the surface should be well polished, no scratches.
For some gemstone varieties, such as quartz, the price per carat is fairly constant as the weight of the stone increases. But in the case of many rarer gems, price increases in a non-linear way as the weight increases. Not only are larger stones much more expensive, but gems cut in stock sizes - what are known in the trade as calibrated sizes - also tend to be more expensive. This is because more material has to be removed to achieve the calibrated size.
Some shapes tend to be priced higher than others, in part because of demand and in part because of material issues in cutting the specific shape. In general, round gems tend to command a premium in the market. Rounds are much less common than ovals, since ovals are usually cut to preserve as much weight of the rough material as possible. Cutting a round gem normally requires a greater loss of the rough stone, and for very expensive materials like sapphire, ruby, alexandrite and others, this can have a significant effect on the price.