Jade minerals

Inosilicates contain single or double chains of tetrahedra. In a single chain structure, the Si to O ratio is 1 3, and in a double chain, it is 4 11. This structural class contains many common rock-forming minerals, including the amphibole and pyroxene groups. Both jade minerals, jadeite, and nephrite, fall within this group. 

Shurvella, H.R, L. Rintoul, and P.M. Fredericks. 2001. Infrared and Raman spectra of jade and jade minerals. Internet Journal of Vibrational Spectroscopy 5(5) 4. (http //www.ijvs.com). Sieveking de, G., et al. 1972. Prehistoric flint mines and their identification as sources of raw... 

A special class of stones are the precious and semiprecious gemstones, with a long history of use in decorations and jewelry. Especially in the Far East and pre-Columbian America, jade was used extensively for carving ceremonial and luxury items. Jade encompasses two different minerals quite similar... 

These differences are considered to be attributed to the dilferences in compositions of rocks and alteration minerals interacted with circulating seawater or modified seawater at elevated temperatures. For example, high K and Li concentrations in the hydrothermal solution in the Mid-Okinawa Trough baek-arc basin (Jade site) are due to the interaction of hydrothermal solution with acidic volcanic rocks (Sakai et al., 1990). It is evident that the chemical compositions of hydrothermal solution are largely alfected by water-rock interaction at elevated temperatures. 

Jade, which has been valued in carving by eastern Asians for centuries, is generally one of two minerals—pyroxene or jadeite (NaAl(Si03)2) and the amphibole nephrite, Ca2(Fe+ )5 and/or Ca2(Mg+ )5(Si40n)2(0H)2. X-ray diffraction has shown the presence of triple chains in nephrite. 

Jade is the common name for gem-quality specimens of two distinctly different mineral species, jadeite and the massive variety of actinolite, called nephrite. The word jade is derived from the Spanish piedra deyjada, meaning stone of the flank. This refers to its popular use as a cure for diseases of the kidneys and liver. Other minerals that have been mistaken for jade, or used as jade imitations include green jasper (quartz), vesuvian (idocrase), massive grossular garnet, chloromelanite (a mixture of dark pyroxenes) (Table 2.10). 

Magnesium is a bright, silver-white alkaline earth metallic element (symbol Mg atomic no. 12). It is widely found as different salts in minerals such as boracite (borate), ankerite and dolomite (carbonates), carnallite (chloride), brucite (hydroxide), periclase (oxide), lazulite (phosphate), amphibole, cummingtonite, enstatite, gamierite, hornblende, humite, hypersthenite, iolite, jade, meUlite, monticellite, olivine, Pennine, saponite, sapphire, serpentine, talc, and tremolite (silicates), and epsomite, kainite, kieserite, and polyhalite (sulfates). 

Gemstones Beryllium is also associated with gemstones. A gemstone is a mineral that can be cut and polished for use in jewelry. Some typical gemstones are jade, sapphire, diamond, ruby, amethyst, emerald, spinel, moonstone, topaz, aquamarine, opal, and turquoise. Gemstones are often used as birthstones, which honor the month in which a person is born. (For instance, the birthstone for April is a diamond.)... 

Figure 10 A quadruple SiO chain defect in a matrix of double (Si04) chains of the amphibole type is shown (a) as a drawing of packing polyhedra and (b) occurring naturally in a crystal fragment of nephrite jade. In (b) the lower inset shows a superposition of the drawing in (a) at a reduced scale and the upper inset shows the computed image of such a defect (Reproduced by permission from Contrib. Mineral. Petrol., 1978, 66, 1)...

A gemstone is a mineral that can be cut and polished to make gems for an ornament or piece of jewelry. At one time, all gemstones were naturally occurring minerals mined from Earth s crust. Today, however, chemists can duplicate natural processes to produce artificial gemstones. Amethyst, emerald, jade, opal, ruby, sapphire, and topaz occur naturally and can also be produced synthetically. 

Figure 5 A dark violet jade cabochon revealed its complex nature under the microscope in reflected light. The darker mineral groundmass was found to be albite feldspar the lighter crystals are jadeite.

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