Elements of Optical Mineralogy: an Introduction to Microscopic Petrography

Abstract

THE descriptive part of Winchell's “Optical Mineralogy” has been completely rewritten and much enlarged to form the second edition. With the exception of a few of the commoner opaque minerals, there are included only natural species the optical properties of which are sufficiently well known to permit their identification microscopic ally. The arrangement of the minerals has been changed, and the system now adopted is the familiar scientific classification of Dana, modified to some extent by advancing knowledge. Certain of the names used are rendered unfamiliar by the adoption of the termination ‘-ite’; for example, chrysotilite for chrysotile. No difficulties arise through such changes, however, owing to an adequate index, which includes synonyms.