Reviews Gems & Gemology, Summer 2017, Vol. 53, No. 2

Book Review: Gem Testing Techniques

Gem Testing Techniques Book Cover
By Alan Hodgkinson, hardcover, 552 pp., publ. by Valerie Hodgkinson, 2015, GBP185.

Although several books on gem testing have been previously published, this particularly comprehensive volume by renowned gemologist Alan Hodgkinson will certainly be a welcome addition to members of the field.  This book is geared towards a general audience from beginners to career gemologists. It is saturated with information, yet isn’t so technical to be impractical. The numerous chapters are organized in broad categories relating to particular physical properties. From acid testing of gem materials to the correct application of ultraviolet light, there is little that Hodgkinson does not cover. This book is well written with great detail. In its 552 pages, the reader will be pleased to find numerous images and diagrams that, while not generally glamorous, are very adequate for aiding the reader in understanding the concepts discussed. Scattered throughout the volume are a number of tips and tricks that the practicing gemologist may find useful to gain information while testing an unknown gem, such as using top lighting to observe pleochroism with a refractometer. Many of the methods require readily available and inexpensive materials, which many gemologists will appreciate; the use of “visual optics” to measure refractive indices with an elongate paper as an indexed scale is one example.

The book is clad in a plain blue hard cover, with silver lettering on the front cover and spine. A ribbon is included for marking one’s place as the reader navigates the pages. The overall quality of the paper, printing and binding appear to be very good. Overall, this book serves as a great reference for gemologists. The decades of experience by the author are apparent when reading through this book. Surely this will be a highly sought-after publication from which hobbyists and professional gemologists alike can benefit.

Nathan Renfro is analytical manager of the gem identification department and microscopist of the inclusion research department at GIA in Carlsbad, California.