Sapphire, the birthstone for September, has a name that is known and prized throughout the world. Yet when the public thinks of sapphire invariably it is as a blue gemstone; the name itself comes from a Latin word that means "blue". This is unfortunate, because sapphire occurs in a wide range of colors and many of these hues are much rarer than the blue shades. The red variety of sapphire has a special name: it is called "ruby". Both sapphire and ruby are a gem varieties of the mineral corundum: the only difference is the trace elements which give them their rich colors. Ruby is the red version, and the term "sapphire" applies to all the non-red colors of the mineral corundum that are cut as gemstones, not just the blue variety. The other colors of sapphire can be just as beautiful and rare - or even rarer - than the blue, but they are usually priced less. Yellow, orange, lavender, and other pastel shades are especially affordable - and often very beautiful. Sapphire gems in colors other than blue are often referred to as fancy sapphire.
Because sapphires represent divine favor, they were the gemstone of choice for kings and high priests. The British Crown Jewels are full of large blue sapphires, the symbol of pure and wise rulers. The most famous and valuable sapphires are a rich intense blue, a truly royal hue. Sapphire is also the birthstone for September, the month when the most babies are born. Ancient lists also name sapphire as a birthstone for April and the gemstone for the sign of Taurus.
Sapphire is perhaps the toughest and most durable gemstone available on the market. With a hardness of 9 on the Mohs scale, sapphire is harder than any other gem but diamond and it has no cleavage plane so it cannot be cut with a single blow like a diamond. In fact, synthetic sapphire is used for scratch-resistant watch crystals, optical scanners, and other instruments because its durability can be trusted. That same durability ensures that sapphire jewelry will be treasured for generations.
Sapphires come from Sri Lanka, Thailand, Australia, and Cambodia. Nigeria, Kenya, Tanzania, China, Vietnam, Madagascar, and the United States. The deposits in Montana in the United States produce a range of fancy colors, mostly from alluvial deposits in the rivers, and deep blue sapphires from one of the world's largest deposits at Yogo Gulch. The sapphires from Yogo Gulch are small in size but they have a beautiful blue. Unfortunately they are found in a hard rock that makes mining difficult, limiting production.
Much of the fine sapphire on the market today comes from Sri Lanka, which produces a wide range of beautiful blues from delicate sky blue colors to rich saturated hues. Yellow sapphires from this locality are magnificent, and may reach sizes of several hundred carats. These large stones are museum pieces, yet are surprisingly inexpensive despite their great rarity. Pink and violet sapphires from Sri Lanka are extremely intense and vibrant in their coloration and are generally much rarer than blue sapphires. Kanchanaburi in Thailand and Pailin in Cambodia are renowned for deep blue, even colors. Two relatively new mining localities are showing promise: Madagascar, which has produced some exceptionally fine stones in small sizes but has no organized mining yet, and Tanzania, which has long produced sapphire in other colors but is starting to produce blue colors as well from a deposit at Tunduru.
The most valuable sapphires have a medium intense, vivid blue color. The best sapphires hold the brightness of their color under all different types of lighting. Any black, gray, or green overtones mixed in with the blue will reduce a stone's value. In general, a more pastel blue would be less preferred than a vivid blue but would be priced higher than an over dark blackish blue color. Many people believe that these blackish “inky” blue sapphires are the most valuable, but this is simply not the case and many folks have never seen a good sapphire. As with all gemstones, sapphires which are "clean" and have few visible inclusions or tiny flaws are the most valuable. However some very fine sapphires, in particular those from Kashmir, have a velvety mist-like texture which enhances the richness of the blue.
The most valuable of the fancy sapphires is a orange-pink or pinkish-orange called "padparadscha" after the lotus blossom. Padparadscha sapphires are very rare and the exact definition has always been a matter of debate: different dealers and different laboratories around the world disagree on the exact color described by this term. Some dealers even argue that the term should not be limited to the pastel shades of Sri Lankan sapphires but should also include the more fiery shades of reddish-orange from the Umba Valley in Tanzania. Padparadscha sapphires sell at a premium, sometimes approaching the price for a fine blue sapphire. Although the exact description is debated, the beauty of these rare gemstones is not, with their delicate blended shades the color of fresh salmon and sunsets. Other very popular shades of fancy sapphires are yellows, bright oranges, lavender and purples, and a bluish green color.
Generally, the more clear and vivid the color, the more valuable the fancy sapphire. If the color is in the pastel range, the clarity should be good: because in lighter tones inclusions are more noticeable, the trade usually prefers the gemstones to be cleaner with fewer visible inclusions. In a lighter colored gemstone, the cut is also more important: it should reflect light back evenly across the face of the stone, making it lively and brilliant. With darker more intense colors, the cut is not as critical because the color creates its own impact. Stones too dark to give good return of light and sparkle are also valued less.
Sapphires are most often cut in a cushion shape - a rounded rectangle - or an oval shape. You can also find smaller sapphires in round brilliant cuts and a wide variety of fancy shapes, including triangles, squares, emerald cuts, marquises, pear shapes, baguette shapes, and cabochon cuts, or smooth domes. Some sapphires with an unusual kind of tiny needle-like inclusions can be cut in a cabochon shape to display a dancing six-rayed white star. Star sapphires, which are becoming more rare, are very popular for men's rings. Star sapphires are judged by the sharpness of the star, the evenness of the rays or "legs" of the star, and the body color of the sapphire. It is extremely rare to find a star-sapphire with a sharp star and a bright blue body color.Article Source: http://EzineArticles.com/?expert=Chris_Ralph
0 comments:
Post a Comment