The Tourmaline Group

By R V Dietrich
Van Nostrand Reinhold Company
1985 ISBN 0-30-442-21857-5

Van Nostrand Reinhold writes:

Throughout history royalty, mineral collectors, and connoisseurs of colored gemstones have treasured tourmalines for their color, color patterns, durability, and natural beauty. In addition to being exquisite showpieces and gemstones, tourmalines also possess qualities—unique structure, physical properties, and chemical compositions—that have been of great interest to chemist, crystallographers, gemologists, geologists, metallurgists, pedologists and physicists, as well as to mineralogists.

The Tourmaline Group examines the features and characteristics that make tourmalines valuable to scientists and collectors alike. With scores of figures, including eight color plates, the book describes and illustrates the eight species of tourmaline comprising this mineral group and tells how the different species originate in diverse kinds of rocks.

Culling information from more than 2000 publications, the Tourmaline Group surveys such topics as:

- Symmetry and Morphological Crystallography—hemimorphism, crystal size, shape and surface features.
- Physical properties—density, hardness, elasticity, and magnetic, thermal, electrical and radioactive properties.
- Crystal structure—diagrams and easy-to-follow explanations illustrating the arrangement of constituent atoms.
- Color and Optical properties—causes of colors, processes for the enhancement of colors, and the relationship between color and other properties.
- Chemistry and Alternation—the ideal formula for each of the species, an evaluation of chemical analyses of both major and trace elements, and the stability of tourmaline under diverse temperature and pressure conditions.
- Synthesis—experiments indicating how tourmaline may be produced by man.

You will also discover how tourmaline has been used by various civilizations. Dr Dietrich traces the historical roots of tourmaline—from a possible description in Theophrastus ‘On Stones—315 B.C), through its use by the Vikings as a ‘sunstone’ navigation compass, to more recent applications in the manufacture of boric acid, in scientific and industrial instruments and in the decorative arts. And, for readers interested in aesthetics, he devotes a separate chapter exploring tourmaline’s use in jewelry art, and as exhibition pieces.

About the author
R V Dietrich has been an active editor of various mineralogical and geological journals and has been the author or co-author of more than a hundred professional papers and 10 books.