The identification of cat's eye gemstones is mainly from the aspects of refractive index, density, hardness, inclusions and other characteristics. Most cat's eye gemstones are gray-brown and translucent, and the opal stones with similar refractive indices are also more. The cat's eye gemstones are all cut into a curved surface. The refractive index itself is only an approximation. If the gemstone is inlaid, its density cannot be directly measured, which makes it difficult to accurately distinguish different cat eye gemstones.
Opal is one of the important variants of the gold emerald mineral family. The hardness is 8.5 degrees, second only to diamonds and red and sapphire. Its color is mostly yellow, yellow brown, yellow green, green white, coffee and other colors. It is obviously golden with color, and its Chinese name is also obtained. A good opal, the bright line of the cat's eye is located in the center of the gemstone face, narrow and clear, and the light is visible. Opal is very precious due to its special light effect, and high-quality opal above 10 carats can be worth millions of dollars. The method for identifying the true and false of the opal is as follows:
1. The main recognition feature of opal is the clear brown-eyed cat's eye. The filamentous inclusions of the opal are rutile, and some are empty tubes. Because these tubular bodies are slender and dense, the cat's eye effect is particularly noticeable, and is also very clear under weaker sources. This is unmatched by other gems.
2. Use a single light source to illuminate the side of the opal, the color of the sides of the opal is different. When you look at the yellow opal from the left side, the left side is honey yellow, the right side is milky white, and when it is illuminated from the right side, its color is just the opposite.
3. Artificial opal is made of fiberglass, red, blue and brown, and the brown-yellow variety is somewhat like natural opal. The difference between the two is that the artificial opal has 2-3 bright bands at the top of the curved shape, and only one natural opal; the sides of the artificial opal are observed with a magnifying glass, and the hexagonal honeycomb structure can be seen; Stone has a lower hardness than natural opal.
The evaluation of opal is based on factors such as color, position of the eyeliner, shape of the gemstone, weight, and the like. High-quality cat's eye gem, the cat's eyeliner should be thin and narrow, and the boundary is clear; the eye should be closed and flexible, and the light should be bright; the cat's eye color should be in sharp contrast with the background; and the cat's eye line should be in the center of the curved surface. When purchasing, the opal should be distinguished from other gemstone cat eyes and artificial cat eyes according to the identification features, and the real opal can be purchased. They can also be distinguished by density determination based on their large differences in density. [2]
Opal is often referred to as "noble gems." Together with the stone, it belongs to one of the world's five precious high-end gemstones. British gem collector Hope has a famous opal stone that has been carved into a shape that symbolizes the altar. There is a torch on the top. The whole gem is spherical and about 1-1.5 inches in diameter. Opal is mainly produced in gas-forming hydrothermal deposits and pegmatite veins. The world's most famous opal origin is in the southwestern part of Sri Lanka, such as Tranabula and Gower, and countries such as Brazil and Russia have also found opals, but they are very rare.
Cotton Woven Fabric,Non Woven Cotton Fabric,Woven 100 Cotton Fabric,Lightweight Woven Cotton Fabric
Shaoxing JingXuan Textile Co.,Ltd. , https://www.jxfabric.com