The English name of the stone (Alexander) is Alexandrite, the Russian name is "ÐлекÑандрит", and the transliteration is "Alexander". The stone is called the purple jade. Because of its green color in the sun and the red color effect under candlelight and incandescent lamps, many poets praised the stone as "the emerald in the day, the ruby ​​in the night". It is said that in 1830, the stone was first discovered in a mining emerald mine in Ural, Russia. The miners dedicated this gemstone with the effect of discoloration to the Russian Crown Prince Alexander II. On his 21st birthday, he The newly discovered gems are set in their own crown and given the name "Alexander Stone", meaning a stone. Like the cat's eye, the stone is a gold emerald in mineralogy, but it has two different gems because of its different optical characteristics. The stone is an orthorhombic system, and the crystal is often short columnar and plate-shaped. It can be discolored (green, red), transparent, translucent to opaque. The refractive index is 1.745-1.754, which is strong in dichroism and heterogeneous. The hardness is 8.5 and the density is 3.73 g/cm 3 . Excellent toughness. A weak red light can appear under both long and short-wave ultraviolet radiation. Due to the trace amount of chromium in the stone (Alexander), it has the strongest transmission to green light, followed by red light transmission, and strong absorption of other light. Therefore, in the daytime, due to the illumination of sunlight, the green light is transmitted most, so it is green, and it is illuminated with sunlight that is similar to white light, and the stone (Alexander) also appears blue. However, in the evening, when red candles, oil lamps or tungsten incandescent lamps are illuminated, the transmitted red light is particularly large, so it appears red. "The stone" is named after it. The color change is very remarkable, and it is the finest treasure. If the color-changing effect and the cat's eye effect are concentrated on one gemstone, it is an extremely rare gemstone with extremely high value. The difference between a stone (Alexander stone) and a similar gem. The current jewellery market is sold with artificial corundum, artificial spinel, artificial synthetic stone, and natural stone. The main basis for visual identification is pleochroism, inclusion characteristics and particle size. Natural rhinestones are dark green or greenish green in daylight and have a particle size of less than 1 cm. Tri-color. It has two phases of gas and liquid inclusions. Artificial corundum stone has only dichromatic properties. Artificial spinel has no pleochroism. Artificial corundum and artificial spinel have a gas, liquid inclusion and curved ribbon. The most reliable method of identification is to determine its density. Evaluation and purchase of stone (Alexander). The stone (Alexander stone) should be based on the perfect color change effect as the basis for evaluation and purchase. In most cases, the stone is dark red to purple in the light; yellowish green and blue-green in daylight. The best grandmother green and ruby ​​red are rarely seen. In the past Russia, the stone (Alexander stone) was deeply loved, and the green and red colors were the colors of the Russian Royal Guard. In some countries, people have changed the stone or moonstone and pearl as the "born stone of June", which symbolizes health, wealth and longevity. It is known as the "stone of health". Both the stone (Alexander stone) and the cat's eye are among the top five precious high-end gemstones in the world. According to reports, a huge stone that weighed 1876 carats was found in Sri Lanka. The polished finished product weighed 65.7 carats and is now housed in the Smithsonian Museum in the United States. The variable stone (Alexander stone) mainly exists in the gas-forming hydrothermal type and pegmatite type deposit. At present, the famous origin of this gem is Sri Lanka, followed by Ural in Russia and Minagiras in Brazil. Fashionable Satin Embroidered Fabric,Satin Embroidered Fabric,Lace Satin Embroidered Fabric,Various Color Embroidered Fabric shaoxing sherry import and export co.,ltd , https://www.sherryfabric.com