Abstract
The technique of producing good polished sections of ore minerals is now well developed, and the methods of mineral identification are highly advanced. The minerals are examined in polished section by means of the reflecting microscope. This will probably continue to be the most convenient means for the study of opaque minerals, since, in general, mineral identification is rapid and fairly accurate, and mineral textures, which are of the utmost importance, may also be observed. Micro-chemical and etch tests are used in this work, aided by the polarizing microscope and observations of color, internal reflection, hardness, magnetism, and special properties. Tables for mineral identification based on the foregoing tests have been written by Murdoch (45),2 Davy and Farnham (19), Farnham (21), Schneiderhöhn and Rapdohr (60), and Short (61).