Elements of optical mineralogy. An introduction to microscopic petrography. Part III. Determinative tables

During the ten years since the publication of the second edition of these tables many new minerals have been described. About fifty of these are included in the third edition of Part II,  which was published in 1933, while nearly seventy are of more recent date. The author has attempted to include in supplementary tables in this printing all the new minerals which seem to be well established and adequately described as to their optical properties. Unfortunately it has not been feasible to incorporate them in the main tables, but this is probably not a very serious difficulty since the minerals in question are all very rare.

It is hoped that the use of colored paper for the table (III) classifying minerals on the basis of their color (and pleochroism) in thin section will make it easy to find the various tables quickly and conveniently

In the preparation of this printing the author has benefited by the assistance and encouragement of his wife, Florence S. Winchell.