Bücher von John Mastin

The Chemistry, Properties and Tests of Precious Stones , is many of the old books which have been considered important throughout the human history. They are now extremely scarce and very expensive antique. So that this work is never forgotten we republish these books in high quality, using the original text and artwork so that they can be preserved for the present and future generations. This whole book has been reformatted, retyped and designed. These books are not made of scanned copies of their original work and hence the text is clear and readable.

"What constitutes a precious stone is the question which, at the onset, rises in the mind, and this question, simple as it seems, is one by no means easy to answer, since what may be considered precious at one time, may cease to be so at another.There are, however, certain minerals which possess distinctive features in their qualities of hardness, colour, transparency, refractability or double refractability to light-beams, which qualities place them in an entirely different class to the minerals of a metallic nature. These particular and non-metallic minerals, therefore, because of their comparative rarity, rise pre-eminently above other minerals, and become actually "precious.""