Weight : 69.0 g Size (mm): L 48.1 x Diameter 25-28 untreated US $1,500 Weight : 1.47 ct Size (mm): L 10.0 x W 4.7 x D 3.49 untreated US $300 Bi-Colored Tourmaline Tourmaline often occurs as long crystals, and especially long crystals may be called "pencil" crystals. The most common type of bi-colored tourmaline is green at one end and pink at the other. Differences in transparency and coloration give each one a unique character. Watermelon Tourmaline As seen in the three watermelons slices to the right, each crystal has different patterns consisting of concentric areas of red, colorless, and green, or red, colorless, and blue. The watermelon tourmaline at the bottom shows three light red bands that intersect with a dark green border. There are beautiful designs created by nature. BI-COLOR AND WATERMELON Rough tourmalines that display more than one color in a single crystal either show a simple separation of color (as pictured below to the left), or they show different colors on the inner and outer portions (as shown below to the right). Stones such as the ones on the left are typically polished into bi-colored tourmaline. The rough on the lower right is often sliced and made into gemstones called "watermelon" tourmalines. Weight : 8.42 ct Size (mm): L 22.8 x Diameter 5.8-6.3 untreated US $600 Weight : 4.30 ct Size (mm): L 15.1 x Diameter5.1-5.9 untreated US $400 Weight : 2.51 ct Size (mm): L 12.9 x W 5.4 x D 3.89 untreated US $500 JUDGING QUALITY Because of the unlimited variety in the combinations of colors and shapes of bi-colored tourmalines, there is also wide latitude in judging their quality, based on personal preference. It is important to first confirm that the gemstone's beauty is well balanced by looking at its overall appearance. Next, even if the individual colors are somewhat light, confirm that the gem has a relatively high transparency and that there is a distinct separation between the colors. The stone's quality is judged as poor if it is cloudy or has large defects, if its balance is thrown off by one color being too strong or too weak, or if the two colors are not distinct. Index Back Next