This book contains classic material dating back to the 1900s and before.
The content has been carefully selected for its interest and relevance
to a modern audience. Carefully selecting the best articles from our
collection we have compiled a series of historical and informative
publications on the subjects of gemology and crystallography. The titles
in this range include "Gemstone Manufacturing" "The Optical Properties
of Gemstones and Crystals" "The Thirty-Two Classes of Crystal Symmetry"
and many more. Each publication has been professionally curated and
includes all details on the original source material. This particular
instalment, "Testing the Colour of Gemstones" contains information on
the dichroscope, filters, lenses and much more. Intended to illustrate
the main aspects of colour testing it is a comprehensive guide for
anyone wishing to obtain a general knowledge of the subject and to
understand the field in its historical context. We are republishing
these classic works in affordable, high quality, modern editions, using
the original text and artwork.