According to the first principles,the lattice structure,elasticity and electronic properties of three kinds of chromites spinel subject to slight structural variation are studied by the pseudowaves plane(PWP) approach based on density functional theory(DFT) and generalized gradient approximation(GGA).

The study indicates that the chemical cemposition types of various typomorphic minerals are as follows: picotite CrOa-a(c)3aa>53%, Ala-a(c)2aaOa-a(c)3aa￡1/411%,MgO￡1/412%, the value of Craa(c)#aa is above 0a±7, pyrope Cra-a(c)2aaOa-a(c)3>5%, Al_a(c)2aaOa-a(c)3aa<19%, t.

The lacunary picotite was found in the 1950′s and over a long period of time it had been mistaken for the magnetite because of its high reflectivity and magnetism.

Morphological characteristics of chrome spinel which is related to diamond primary deposits;

As a kind of accessory mineral,chrome spinel contained in ultrabasic rocksis complicated in chemical composition,stable in physical property,and strong in antial-teration ability.

The main minerals in the rocks are olivine, chromium spinel, diopside, endiopside, and/or garnet, orthopyroxene, amphibole and phlogopite.

Petrology of ultramafic rock in Darbut ophiolite (Xinjiang),evidence from Cr-spinel.;

Alteration Characteristics of Ore-forming Cr-spinel in the Sartokay Chromite Ore District, Xinjiang

Results from ICP-MS and EPMA analysis show that serpentinite is dominated by Cr-spinel group minerals with an abundance of Cr up to 6187×10-6 and Cr#(=100Cr/(Cr+Al))ranging between 60 and 69,indicating that the formation environment may have relations with supra-subduction zone ophiolite.