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Understanding the Gem Minerals: A Practical Guide

Understanding the Gem Minerals: A Practical Guide book

Special Publication Volume 12

By William Revell Phillips and James Shigley

This book is intended to bridge the gap between the complex science of mineralogy and the rock hound’s field guide of rocks and minerals. We begin with the elements, the building blocks of minerals, and which of the ninety-two naturally occurring elements are really important to us in building crystals of the minerals we call gems. The arrangement of these building blocks is as important as the identity of the elements themselves, and the crystal structure (ie., atom arrangement) is expressed by crystal form and symmetry resulting in crystal systems and classes.

Softcover. 272 pages. 2016.

MAC Member Price: $56 CAD/USD

Publication Price $70.00 CAD/USD
ID: SP-12
ISBN: 978-0-921294-58-0


The behaviour of light in a gem crystal determines its brilliance and dispersion and is completely unlike light’s familiar behaviour in air, water, or glass. Specific elements and imperfections in crystal structure yield the colour of our gems which may be stable or unstable. Element bonding forces in crystals are metallic, covalent or ionic. Metallic bonding yields soft metals like gold and silver or hard metals like tungsten and chromium depending on the atom arrangement. Platinum may be either hard or soft. Diamond is truly unique in both properties and geological occurrence. Most minerals are ionic or mixed bonds. Most minerals are silicates (ie., containing SiO2), and may be blocky, fibrous, or sheet structures depending on the number of oxygen ions shared between two silicon ions. The chemical formula and crystal system of a mineral are not trivial bits of information– they hold a world of information for those who understand the gem minerals.

This book is entitled “Understanding the Gem Minerals” for a reason. There is much to know and learn for those who care.

– William Revell Phillips

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