Come share our fascination with the gems that display special characteristics—not the ones that lie on velvet looking beautiful because of trace elements and pigment, but the largely indistinct category, phenomenal gems, the gems that appear to do tricks. Optical “tricks” are based on the physics of light and materials. The way light moves through gems determines the patterns we see dancing before our eyes. It is as if the wonders of the world were compressed into each tiny, splendid object. How can anyone resist appreciating the quintessence of nature that may have taken millions of years to produce and thousands of people diving from fleets of ships or moving mountains to obtain?
As much as we admire the visual effects, we have long felt that the field needed systematizing. Curious about the various structures, we decided to create this book to sort the phenomena into categories, looking at the broad similarities first and the details of the special cases second. The only organization that gives a sense of appropriateness is what parses with science. For history’s sake, we include scientific names when they exist, but for ease, we describe the effects in plain terms. We hope that our arrangement of categories simplifies the work of the gem establishment and clarifies the field for the audience of gem lovers and buyers.
To discover which properties create what effects, we sought the expertise of Dr. John Emmett, the renowned physicist who has turned a practiced and discerning eye on gemology. To assure the mineralogical data, we turned to John S. White, former Curator of the National Mineral and Gem Collection, Smithsonian Institution. Many other enthusiastic friends and colleagues have shared their ideas and the treasures in their personal and professional collections.
Each phenomenon depends on three aspects of light: human vision; the physical structure of the gem; and the color, or wavelength, of the source of illumination. The parts and chapters comprise groups of gems displaying a particular set of characteristics in nature’s vast array. Of course, categories are but a means to simplify the stunning diversity of phenomena on exhibit around us. No matter how elegantly we draw distinctions, there will be those gems that show up in two or three categories.
During the thousands of years of human history, people have prized and puzzled over what phenomenal gems concealed and revealed. Before scientists discovered the causes for most of the patterns, such treasures must have appeared supernatural. They still entrance us as they blink, glow, sparkle, shimmer, and change color. Altering light, they delight our senses and stir our imaginations. Depending on their structure, all phenomenal gems absorb, refract, and reflect light in various extraordinary ways.
Discover a range of showy surprises to suit your every taste and mood. As Robin Banchik, of Crystalarium, characterizes the passion for phenomenal stones, let’s enjoy indulging “our obsession for ‘esoteric weirdness.’” Join us as we present structures one chapter at a time to show how these “gems that do tricks” perform their magic.