The stone we know as garnet, January’s birthstone, is not a single mineral, but a set of closely related silicate minerals with slight variations in chemical composition and trace elements. Prized since antiquity, garnets have been found in Egyptian tombs and Roman archeological sites. While red garnets are the most well-known type of this gemstone, garnets can also be found in other colors, such as green and orange. This gives those who have January birthdays some intriguing options for birthstone jewelry.
Because there is so much variation in the chemical composition of garnets, they are divided into categories called species. Of the twenty species of garnet, only a handful are used as gemstones—almandine, andradite, grossular, pyrope, rhodolite, and spessartine. A species may be further broken down into varieties, based on color. For example, green tsavorite is a variety of grossular, and rhodolite is a purplish variety of pyrope-andradite. With a Mohs hardness of 6.5 to 7.5, garnet is sturdy enough for use in most jewelry, with the exception of rings that will be worn on a daily basis.
The value of a garnet depends on the usual four factors that influence any transparent gemstone’s worth—color, clarity, cut, and carats—but how each of those factors comes into play can vary with the type of garnet in question. In general, the more vibrant and saturated the hue of a garnet, the more it is worth. However, a superior example of a rare hue will bring a much higher price than a more widely available color such as traditional red.
Expectations of clarity in a garnet vary by the species. Red garnets can be readily found without eye-visible inclusions. However, some orange types of garnets are usually found with eye-visible inclusions, which means that having such inclusions will not dramatically affect their price. One variety of green garnet, known as demantoid, is sometimes found with hair-like inclusions called horsetails, which are actually considered to increase its value.
The influence of cut and carat weight on a garnet’s value is also affected by a garnet’s species. Garnets are often cut into standard shapes and sizes for setting into jewelry, although the rarer types will usually be cut according to the shape and cutting style that allow more of the stone’s weight to be retained, or which will best display the characteristics of its variety. Whatever the cut, it should enhance the stone’s brilliance. Some varieties like demantoid and tsavorite are usually found only in smaller sizes, which means that their value goes up dramatically as their size increases. However, most garnets are widely available in larger carat sizes, so the per-carat cost does not go up as much for bigger stones.
Whenever you’re in the market for fine jewelry, it pays to check out purchasing at auction. Auctions give you the opportunity to buy at prices significantly below retail, while offering options you won’t find at a mall jeweler. You can bid on a constantly updated selection of quality pieces in Auction King’s live online auction from the convenience of your own home. Sign up for a free online account today to get started.