The Elements of Blowpipe Analysis

by Frederick Hutton Getman

CHAPTER IV

BEHAVIOR OF SOME OF THE PRINCIPAL ORES BEFORE THE BLOWPIPE

For the sake of practice, and as a fitting introduction to "Determinative Mineralogy," this chapter is appended. It is not intended to give a detailed account of the minerals, but rather to set before the student the most marked characters, such as hardness, specific gravity, color, lustre, etc.

To determine the hardness of a mineral, we try to scratch it with the minerals forming an arbitrary "scale of hardness," proceeding successively from the softest to the hardest. When we say that a certain mineral has hardness = 4, we mean that the mineral is scratched by 4 on the scale, and that 4 on the scale is scratched by the mineral. The scale of hardness chiefly in use is the Mohs-Breithaupt scale, which is as follows:—

1. Talc, common laminated light green variety.

2. Gypsum, crystallized.

3. Calcareous spar, transparent variety.

4. Fluor spar, crystalline.

5. Apatite, transparent.