Gübelin, Eduard J. & Koivula, John I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Opinio Publishers, Basel, Switzerland, 830 pp. ISBN 978-3855040957

The author makes his first pilgrimage to Burma's Mogok Stone Tract.

The phenomenon of pleochroism in doubly refractive (DR) gemstones is described, as it relates to overall color appearance in the context of faceted gems. With strongly pleochroic gems, pleochroism can be seen in faceted gems, even if the table facet is oriented perpendicular to an optic axis. This is because facets change the direction of light as it moves through the gem.

Ruby & Sapphire

Richard W. Hughes  |  1997

Ruby & Sapphire is widely acknowledged as one of the finest gemology books ever published. Not just an update of his previous volumes on ruby and sapphire, it represents something rarely seen in a technical book, a fusion of accurate science and spirited, accessible prose. Within its pages, one finds information on prices, quality analysis, sources, history, treatments and identification. Featuring over 300 color photos and 2500 references, this now out-of-print volume is today highly sought after by collectors and gemologists, who pay as much as $1000 or more for the privilege of owning a copy.

Out-of-print. Click here to search for a copy

Solid inclusions have been used by gemologists as a means of determining origin. While there is a great deal of overlap from one source to another, there are also important differences. For example, while apatite has been identified in sapphire from Madagascar, Myanmar and Sri Lanka, apatite has never been identified in sapphire from Kashmir. Thus the purpose of this article is to give a full listing of solid inclusions in gem corundums from around the world, with each occurrence fully referenced. This is provided with the goal of making origin determination of ruby and sapphire more accurate.

Ruby & Sapphire  •  A Collector's Guide

Richard W. Hughes  |  2014

Few gems capture the imagination like ruby and sapphire. This book removes the cloak of
 an otherwise secret world
. Drawing on a lifetime’s experience, 
the author ventures around the globe for the
 finest specimens, in the process allowing readers to discover 
the people and places where these rare gems are 
found, along with the story of the stones themselves. Throughout the text, Hughes guides readers with
 the steady connoisseur's eye, explaining what collectors should look for. For many pieces, actual
 auction prices are given, aiding collectors in their 
buying decisions. Illustrated with more than 300 color
 photographs, this is a visual and intellectual feast of
 the most delicious order.

Ruby & Sapphire • A Collector's Guide order page

Ruby & Sapphire  •  A Gemologist's Guide

Richard W. Hughes, with Wimon Manorotkul & E. Billie Hughes  |  2017

Designed as a companion to Ruby & Sapphire: A Collector's Guide, this massive volume is aimed specifically at working gemologists, appraisers and students. Based on Richard W. Hughes' 1997 classic, Ruby & Sapphire, this edition is fully updated. The product of nearly 40 years of firsthand experience and research, it covers every aspect of the subject from A–Z. History, sources, prices, quality analysis, synthetics and treatments, everything is here. With over 1000 photos, maps and illustrations and 3500 references, Ruby & Sapphire—A Gemologist’s Guide represents the most comprehensive book ever written on a single precious stone.

Ruby & Sapphire •  A Gemologist's Guide Order Page 

A discussion of the literature of ruby and sapphire (corundum), with particular emphasis on the most collectible books covering ruby and sapphire around the world.

A brief description of the color types for ruby and sapphire used at Lotus Gemology.

From Peacock to Pigeon's Blood  •  An Introduction to Ruby & Sapphire Colors

Lotus Gemology  |  2017

An introduction to the ruby & sapphire color types used at Lotus Gemology.

From Peacock to Pigeon's Blood Order Page 

World auction records for ruby, sapphire and spinel.

Ruby, Sapphire & Spinel: An Archaeological, Textual and Cultural Study By Derek J. Content, 2016. Brepols Publishers, Turnhout, Belgium, www.brepols.net, 452 pages, illus., ISBN 978-2503568089. €150.00 hardcover.

A discussion of rutile silk in corundum and its use in detecting artificial heat treatment. Careful examination of these "silk" inclusions can provide vital clues to unmask heated gems.

In 1878, the noted Austrian mineralogist, Gustav Tschermak von Seysenegg [1836–1927], was the first to properly identify silk in corundum, finding it to be composed of the mineral rutile (TiO₂). An English translation of his landmark paper is included, along with the original German version.

Sapphire is one of the classic gems. In this article, Lotus Gemology's resident connoisseur casts a discerning eye at the factors that contribute to quality in this legendary precious stone.

A Burmese sapphire shows a celestial scene both externally and internally.

In search of ruby and sapphire on the lost Isle of Madagascar.

The examination of a yellow sapphire provides a lesson in the power of gemological microscopy.

No one can go it alone. We would like to thank the many individuals who have helped us over the years. Please excuse us if we have missed anyone.

Family

• Phyllis and Robert Hughes, RWH's mother and father, USA
• David Hughes & Andrea Carney, RWH's brother and sister-in-law, USA
• The extended Manorotkul clan, Thailand

Special Thanks

• Marc Bogerd, Thailand
• John Emmett & Karen Palmer, Crystal Chemistry, USA
• Olivier Galibert, Hong Kong
• Gem and Jewelry Institute of Thailand, (with special thanks to Wilawan Atichat, Pornsawat Wathanakul, Chakkaphan Sutthirat, Thanong Leelawatanasuk, Visut Pisutha-Arnond, Wandee Mansrisuk)
• John & Kristi Koivula, microWorld of Gems & the GIA
• William Larson, Jeanne Larson, Josh Hall, Gabriel Mattice, John McClean, Jason Stephenson, William Larson, Jr., Carl Larson and the rest of the gang at Pala International, USA
• Vincent Pardieu, Fieldgemology.org & GIA, Thailand
• Julie Poli, Vietnam
• Dana Schorr (r.i.p.), Schorr Marketing, USA

Merci

• Lafir M. Abbas, The Choice, Sri Lanka
• Ahmadjan Abduriyim, GIA, Japan
• Lewis Allen, Lucas Amelung & Hans Pfister, Crown Color, Thailand & Hong Kong
• Rick Allen, Gem-Land Adventures, USA
• Apporv, Siam Pioneer Gems, Thailand
• E. "Hanuman" Aspler, Ganoksin.com, Thailand
• Zaheer Azizi, Azizi Enterprises, Thailand
• Walter Balmer, Switzerland
• Tom Banker, Thailand
• Bill Barker (r.i.p.), Barker & Co., USA
• Adolfo & Marta de Basilio, Spain
• Steven Baughman, USA
• Joe & Pirapan Belmont, KV Gems, Thailand
• Steve Bennett, GemsTV, UK
• Jeffery Bergman, Primagem, Thailand
• Riccardo Bertoncelli, Italy
• Jeffrey Bilgore, USA
• Rick Blankenhorn, the Gemmary, USA
• Dudley Blauwet & Kevin Ringer, Mountain Minerals, USA
• Edward Boehm, RareSource.com, USA
• Gary Bowersox, Geovisions, USA
• George Bosshart (r.i.p.), Switzerland
• Eric Braunwart, Columbia Gem House, USA
• James Breski, USA
• Barry Broman, USA
• Cal Brown, USA
• Peter & Eileen Brown, Australia
• Richard Brown, Thailand
• Grahame Browne (r.i.p.), Australia
• Charles Cameron, USA
• Anne Carroll Marshall, Hong Kong
• Cartier, France
• Loretta Castoro, USA
• Tom Chatham, Chatham Gems, USA
• Thongsak Chintakanrock, Expert Gems, Thailand
• Christie’s, various locations
• Fred & Sopha Chu, Prosper International, Thailand
• Ed Cleveland, Kashmir Blue, USA
• Terry Coldham, Australia
• Chris Cooney, Gem Mountain, USA
• Paula Crevoshay & Martin Bell, Crevoshay Co., USA
• Tom Cushman, Madagascar
• Bruce Davidson (r.i.p.), Sri Lanka
• Dona Dirlam, GIA Library, USA
• Katia Djevahirdjian, Hrand Djevahirdjian, Switzerland
• Richard Drucker & Stuart Robertson, Gemworld, USA
• Garry Du Toit, Thailand
• Manfred Eickhorst, Eickhorst, Germany
• Jim & Jennie Elliot, Australia
• Hemi Englisher, Gemcal, Thailand
• Thomas Färber, Switzerland
• Elaine Ferrari-Santhon, USA
• Conny Forsberg, Sweden
• Thomas Frieden, Frieden & Co., Switzerland
• Masaki Furuya, Japan
• Lyndsey Roy Hamm, Canada
• Ian Harebottle, Adrian Banks & Gabriella Harvey, London
• Gems By Nomads, Thailand
• Didier Giard, France
• David Glickman (r.i.p.), Thailand
• Jan Goodman, Jan Goodman Co., Thailand
• Gene Goldsand, USA
• Mike and Pat Grey, Coast-to-Coast Gems, USA
• Daniel Grondin, Madagascar
• Peter Grumitt, Apsara Gems, UK
• Eduard Gübelin (r.i.p.), Switzerland
• Thomas Hainschwang, GGTL Laboratories, Liechtenstein
• Tino Hammid (r.i.p.), Tino Hammid Photography, USA
• Henry Hänni, Switzerland
• Hayley Henning, TanzaniteOne, USA
• Han Htun, Stalwart Gems & Laboratory, Myanmar
• George Harlow, American Museum of Natural History, USA
• Alan & Charlene Hodgekinson, UK
• Hpone-Phyo Kan-Nyunt, Gübelin Gem Lab, Hong Kong
• Simon Hsu, Sino Resources, Hong Kong
• Neal Hurni, Lewis and Clark Sapphires, USA
• Christina Iu, Japan
• Kunal Jain, Sachi Gems & Tools, Thailand
• Matee Jungsanguansith, World Sapphire, Thailand
• Leonard S.N. Kalindekafe & Levison Wesley Undi, Malawi
• Susie & Kennedy Kamwathi, Kennedy's Gems, Kenya
• Robert Kane, Fine Gems International, USA
• John Kanyangira, Rwanda
• Alice Keller, USA
• Allen Kleiman, USA
• Ajith Konara, Kaluganga Gem Centre, Sri Lanka
• Nickolai Kouznetzov, Russia
• Rick Krementz, USA
• Michael Krzemnicki, Laurent Carier & Jean-Pierre Chalain, SSEF, Switzerland
• Tony Laughter, USA
• Brendan Laurs, USA
• Barbara Lawrence, USA
• Tom Lee, USA
• Alexander Leuenberger, Switzerland
• Peter Lyckberg, Sweden
• Louis Lo, Hong Kong
• Abdul Mahomed, Royal Group, Malawi
• Jeff Mason & Don Kay, Mason-Kay, USA
• Neal Masson, Thailand
• Antoinette Matlins, USA
• Shane McLure, GIA, USA
• Yianni Melas, Cyprus
• Wong Ming, Hong Kong
• Justin Mmbaga, Longido, Tanzania
• Robert, Fred and Pascal Mouawad
• Roland Naftule, USA
• Omi & Niveet Nagpal, Omi Gems, USA
• Kurt Nassau (r.i.p.), USA
• Robert G. Nkini, Tanzania
• Marc Noverraz, Madagascar
• Daniel Nyfeler & Lore Kiefert, Gübelin Gem Lab, Switzerland
• Donald A. Palmieri, USA
• Adam Parker, York Museum, UK
• Adolf Peretti, GRS, Bangkok
• Paul Picus, Mexico
• Ronnachai Porwongsawang, Elegant Gems, Thailand
• Jeffrey Post & Russell Feather, Smithsonian Institution, USA
• Todd A. Pownell, USA
• Charlotte Preston (r.i.p.), USA
• Prida Tiasuwan, Pranda, Thailand
• Ali Sanaei Rad, Central Bank of Iran
• Nirina Rakotosaona, Madagascar
• Peter Read (r.i.p.), UK
• Ricardo V. Reyes
• James Riley, UK
• Elaine Rohrbach, Gem-Fare, USA
• The Rogers Family, USA & Thailand
• Doug Ross, USA
• George Rossman, CalTech, USA
• Chavalit Salwala, Thai Lapidary, Thailand
• Saw Naung U (r.i.p.), Daw Khin Soe Myint, Saw Sanda Soe & Ei Ei, Myanmar
• Alberto Scarani & Mikko Åstrom of GemmoRaman, Italy & Finland
• Ken & Sriurai Scarratt, Thailand
• Joseph Schall, USA
• Jeff Scovil, Scovil Photography, USA
• Rogers S. Sezinga, Tanzania
• John, Mark & Eric Saul, France & Tanzania
• Jon Sigerman, USA
• Santpal Sinchawla, Sant Enterprises, Thailand
• Manus Siripatvanich, House of Goldsmiths, Thailand
• Elise Skalwold, Cornell University, USA
• Christopher Smith, AGL, USA
• Mark Smith, Thai-Lanka Trading, Thailand
• Somkhit Sodkaew, Sapphire Miners Cyangugu, Rwanda
• Sotheby’s, various locations
• Tim Spauwen, The Netherlands
• David Squires, InStore magazine, USA
• Martin Steinbach, Germany
• Judy Steinberg-Bricker, USA
• Issac Stern, Thailand
• John and Linda Stimson, Rocks of Ages, USA
• Patrick Streeter, UK
• Chetan and Kaimesh Sukhadia, Sukhadia Stones, Thailand
• Abe Latif Suleman, Tucker International, Tanzania
• Sarawut Sunantra, Wongwan Gems, Thailand
• Maha Tannous, USA
• Tay Thye Sun, Singapore
• Por Kuang Tang, PK Gems and Gold, Thailand
• Petcharaporn Tantiwong, Lapis Gemologists, Thailand
• Tom & Myriam Tashey, Professional Gem Sciences, USA
• Ted & Angelo Themelis, Gemlab, Thailand
• Matt Thompson, USA
• Veerasak and Tanyaporn Trirotanan, Veerasak Gems, Thailand
• Votha Un (r.i.p.), Cambodia
• Harold & Erica Van Pelt, USA
• Jim Varak, Australia
• Ben Vardi of Vardi Coloredhouse
• Fred (r.i.p.) & Charlotte Ward, USA
• Simon & Laurie Watt, Mayer & Watt, USA
• Robert & Rolf Weiser, USA
• David Weinberg, Multicolour Gems, Bangkok
• Robert Weldon, GIA, Thailand
• Bear & Cara Williams, USA
• Jack Wilson, Australia
• Richard & Rebekah Wise, USA
• John Woodmark & Bruce Moore, Desert Sun Mining & Gems, USA
• Larry Woods, Jewels from the Woods, USA
• Vlad Yavorskyy, Yavorskyy, Thailand
• Wilson Yuen, Able Lapidary, Hong Kong
• Philip Zahm & family, Philip Zahm Designs, USA
• Ray & Sheila Zajicek, Equatorian Imports, USA
• Gamini Zoysa, Mincraft, Sri Lanka
• Urs Zwyssig, Thailand

Virtually all gemologists are aware of the curved growth lines and gas bubbles in Verneuil (flame-fusion) synthetic corundum, but few understand exactly why they occur and how they are distributed in these stones. This article clarifies these important identifying features.