镁铬铁矿

Spinel is a compound of magnesia and alumina(Al2O3) and is thus a magnesium aluminate(MgAl2O4), found as accessories in igneous rocks, in metamorphosed aluminous schists, in contact metamorphosed limestones and sometimes in high temperature iore veins.

尖晶石主要成分是氧化镁和氧化铝，结晶习性是等轴晶系漂亮的正八面体。镁被铁置换就是铁尖晶石，被锌置换就是锌尖晶石，铁完全置换镁形成磁铁矿，铬置换铁尖晶石形成铬铁矿，这些类质同相的等轴晶系都是八面体结晶的尖晶石族矿物。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。