Chemical Composition and Physical Properties of Jade

As an important category of gems, jade enjoys the dominating role on some culture, such as in China. The reason why jade has been so popular in the heart of Chinese for such a long time originated in the value orientation of the culture and many other aspects of the country, while the advantages of jade itself cannot be ignored as well, today I will introduce you the chemical composition and physical properties of Jade regardless of its cultural meaning.In mineralogy, jade belongs to the rock category which is composed of many tiny minerals. The minerals are composed of jadeite NaAl [Si2O6], sodium chromium pyroxene NaCr [Si2O6] and aegirine NaFe [Si2O6] in different proportions. The pure jadeite is colorless, sodium chromium pyroxene is mostly brilliant green and aegirine is mostly light green. The degrees of proportions of different minerals would lead to the vast difference on the color and texture of jade. Expect the above three minerals within the jade, there are other categories such as minerals of amphibole, feldspar, even quartz and chromite can be contained. On the surface of the jade, minerals like limonite, hematite, kaolinite ect. The color of limonite and hematite are brown-red, red and yellow, which would lead to the red and brow surface of the jade.The proportion of jade is between 3.24 and 3.43, which enjoys the higher proportion among gems, thus connoisseur distinguish jade from imitations jade made of glass or quartz by weighing them item with hand. The expert can identify the imitation or natural one in that jade is absolutely weightier than the counterfeit ones.The Mohs hardness of jade is of 6.5 to 7, which is higher than 5.5 of nephrite but lower than the 7 of quartz, while when compared with diamond whose hardness is 10, it is much lower, thus among all the jades, emerald is of the most hardness. There is a method to identify the natural or imitation emerald popularized among the public, which is said to use the jade scratch glass, if the glass can be scratched, then the jade is natural emerald, if not, it is imitation one, while in fact the method is wrong in that by hardness alone cannot come to the identification results. Emerald is of high toughness, which is determined by its interwoven and layered structure. Toughness is the nature to against compression and strike. Diamond is of high hardness, while its toughness is not that good, thus when the diamond ring worn on your fingers have a collision with something hard and the direction of the force is consistent with the direction of the cleavage coincidently, the breaking cases of the diamond might occurs. The extreme example cannot illustrate the case that hardest diamond is indestructible; it is the jade that of a larger degree of toughness can withstand a lot of pressure.