The Structure of Minerals

Abstract

The uniformity of natural crystal forms led mineralogists to the belief, even in the earliest days of the science, that the reasons for this uniformity could be found in their internal structure. In 1611 Johannes Kepler, through observations of the hexagonal forms of snowflakes, theorized that these skeletal forms were the result of an ordered arrangement of equalsized vapor droplets at low temperatures. In 1784 René Just Haűy, professor of mineralogy at the Sorbonne, also speculated on the structure of crystals. In his book Essai d’une théorie sur la structure des crystaux he expressed the theory that all crystals are built up of minute c1eavage bodies, the “molécules intégrantes,” that produce regular but varied crystal forms during the crystals’ growth. However, many physical properties of minerals did not support the theory of growth of “integrating molecules” forming solid bodies without intervening spaces or gaps.