Secrets of the Gem Trade: The Connoisseur's Guide to Precious GemstonesAs the sub-title suggests, this is the consumer's guide to precious gemstones. Divided into two parts: In plain non-technical language, Part I redefines preciousness and gently guides the reader toward a real understanding of those criteria that make a gemstone. Part II contains a series of individual essays that apply the criteria of connoisseurship to 35 of today's most important gemstones. The book covers precious stones old and new including diamond, pearl, tourmaline, sapphire, chalcedony, spinel, ruby, and garnet. |
From inside the book
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Page 109
... refractive index . that virtually matches the refractive index of emerald , making it impossible outdoor type ) . Multicolor effect , the tendency for a gem to show tonal variations of green in the face - up position ( see Part I ) ...
... refractive index . that virtually matches the refractive index of emerald , making it impossible outdoor type ) . Multicolor effect , the tendency for a gem to show tonal variations of green in the face - up position ( see Part I ) ...
Page 127
... refractive : light that enters the gem is divided into two rays . Tsavorite , however , like all garnets , is singly refractive . The key difference between emerald and tsavorite is refraction and dispersion . The refractive index of ...
... refractive : light that enters the gem is divided into two rays . Tsavorite , however , like all garnets , is singly refractive . The key difference between emerald and tsavorite is refraction and dispersion . The refractive index of ...
Page 250
... refractive qualities.203 Spinel , however , is singly refractive and rarely exhibits the dramatic multicolor effect or color bleeding normally seen in ruby ( see Chapter 4 ) . Spinel is a tough and durable gemstone . At eight on the ...
... refractive qualities.203 Spinel , however , is singly refractive and rarely exhibits the dramatic multicolor effect or color bleeding normally seen in ruby ( see Chapter 4 ) . Spinel is a tough and durable gemstone . At eight on the ...
Contents
PART II | 10 |
The Geometry of beauty | 22 |
Secrets of the trade | 37 |
Copyright | |
43 other sections not shown
Other editions - View all
Secrets of the Gem Trade: The Connoisseur's Guide to Precious Gemstones Richard W. Wise No preview available - 2016 |
Secrets of the Gem Trade: The Connoisseur's Guide to Precious Gemstones Richard W. Wise No preview available - 2006 |
Common terms and phrases
aficionado agate alexandrite amethyst appear aquamarine beauty blue diamonds blue sapphire bluish body color Brazilian brilliance brown brownish Burma cabochon carat carnelian cat's-eye chalcedony chrysocolla chrysoprase clarity grade collector color grade colored gemstones colored stones colorless diamonds connoisseur connoisseurship courtesy crystal cultured pearls dark daylight dealers described diamond color diamond grading eighty percent emerald evaluation exhibit face-up faceted fancy color diamonds finest fluorescent freshwater pearls garnet gem varieties Gemological Gemological Institute gemologist Gems & Gemology gemstones GIA-GTL grading reports incandescent light Jeff Scovil key color lapidary lapis lighting environment luster multicolor effect nacre normally opal orange padparadscha Paraiba parcel percent tone pinkish precious primary hue purple purplish rare refractive refractive index saturation and tone saturation modifier secondary hue South Sea pearls specific spessartite spinel Stephen Hofer tanzanite term tonal topaz tourmaline translucent transparency tsavorite visible inclusions visually pure vivid yellow yellowish