One of the main attractions of colored gemstones is, of course, color. The most valuable colored stones are those with vivid and intense color, such as ruby, emerald and sapphire. However, sometimes a jewelry design calls for a white or colorless gem. When diamond is not practical or cost-effective for the design, the colored gemstone world offers a number of interesting white alternatives.
When small pieces are needed for side stones, the most popular melee is white sapphire. With its excellent hardness (9 on the Mohs scale) and high refractive index, sapphire can be an acceptable substitute for diamond. It can usually be found in sizes ranging from 2 mm, in both round and square shapes.
While sapphire is by far the most common white gemstone in small sizes, there are a number of choices in larger stones. The most common options are sapphire, zircon and topaz. White sapphire can be found in sizes up to several carats in a wide range of shapes: heart, princess-cut, marquise, oval and trillions are common. Round white sapphires usually command a premium, particularly in calibrated sizes.
White zircon is a brilliant gem with a high refractive index. Before the introduction of diamond simulants like cubic zirconia, white zircon was often used as a diamond replacement. Though not quite as hard as sapphire, white zircon is more affordable. The same is true for white topaz. When a white gemstone is needed in a large size - over 5 carats - topaz is the obvious choice. White topaz can often be found at prices under $10 per carat, even in stones weighing over 10 carats.
There are also some lesser known colorless gemstones that offer interesting alternatives. The white beryl known as goshenite has very good hardness (7.5 to 8 on the Mohs scale) and is suitable for all kinds of jewelry. Although it does not have as high a refractive index as sapphire or zircon, it has very good clarity. In fact, goshenite was once used for manufacturing eyeglasses and lenses owing to its excellent transparency. Another rare colorless gem is danburite. With a hardness of 7 to 7.5, danburite is also durable enough for rings. Since it has a refractive index about the same as tourmaline, it can be faceted with good results.
- Впервые опубликовано: March-22-2010
- Последняя редакция: October-16-2018
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