Formation of Precious Stones and Gems

All precious stones are transparent, or at least translucent, from which it may be concluded that the matter of which each consists is homogeneous. Now this homogeneity could never have been attained by the mixture of their elements in the solid state, however finely these may have been pulverized, and hence they must have been in the condition of either gases or liquids. Nature has a multitude of either gases or liquids. Nature has a multitude of means by which these trfQUARTZansformations of matter are effected, all referable to three general processes:--

1st. Direct fusion of the substance by the action solely of heat.

2d. Dissolution of the substance by the aid of foreign substances at variable temperatures.

3d. Bringing together, in the state of vapours, substances destined to become the elements of the stone.

From the point of view of their formation, therefore, precious stones may be naturally divided into two classes.

The first comprehends stones produced by direct fusion, by crystallization in an excess of their melted substance, by volatilization of their elements; in a word, by the direct intervention of heat.

The second includes stones which have been formed in the midst of a solution of which water has been generally one of the constituent elements.

Hence some precious stones are met with in those portions of our globe which have been subjected to a high temperature, while others are found in those that have never supported such a temperature, or what comes to the same thing, that have been perfectly cooled at the period when they furnished to the water the elements of the stones of which we are speaking.