Trigonal zinc blende

Note, the tetragonal distortion influence the Cs modulus exclusively, the trigonal - the c/ modulus. This fact can give us an instrument to determine the type of local distortions in an ultrasonic experiment carried out in a zinc-blende crystal the distortions can be pointed out with the help of temperature dependences of the elastic moduli. 

The relative abundance of zinc in the Earth s crust is about 75 mg/kg (i.e., ppm wt.), less than vanadium, nickel, and chromium. Major zinc minerals are the sulfide sphalerite or blende [ZnS, cubic], smithsonite [ZnCOj, trigonal], and hemimorphite or calamine [Zn SijO/OHjj.HjO, monoclinic] and franklinite [ZnFe O, cubic]. Of these mainly the sphalerite is used as zinc ore. Moreover, in ore deposits, sphalerite is often associated with galena and pyrite, and because it contains nonnegligible amounts of impurities such as Cd, In, and Ge, sphalerite is the principal source of these metals as byproducts. In 2002, the world zinc concentrate production totaled ca. 8.728 x 10 tonnes of contained zinc. With roughly 233 mines operating worldwide, the Asia-Pacific region, with 108 mines and 3.794 X 10 tonnes per annum, and the Americas, with 82 mines and 3.803 x 10 tonnes annualy,... 

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