Eighteenth Annual Sinkankas Symposium – Alexandrite and Other Color-Change Gemstones

• 

  Eighteenth Annual Sinkankas Symposium
      Alexandrite and Other Color-Change Gemstones

  April 25 through June 13, 2022

  (pre-recorded sessions on-demand)

  co-sponsored by
  the Gemological Institute of America, the Geo-Literary Society
  and the Gemological Society of San Diego

  Rough and cut alexandrite. Photo by Robert Weldon. © GIA.
  

• 

  Sinkankas Symposium – 2022

  Evan Caplan
  William Larson
  Dr. Çiğdem Lüle
  Dr. Sally Eaton-Magaña
  Niveet Nagpal
  Nathan Renfro
  Stuart Robertson
  Dr. Aaron Palke and Dr. George Rossman
  Wim Vertriest
  Robert Weldon

  A pair of faceted alexandrites: at left photographed in daylight-equivalent lighting, at right photographed in incandescent light. Photo by Robert Weldon. © GIA.

• 

  The Sinkankas Symposium

  "The best gem mineral symposium in North America."

  — John Koivula
  Analytical Microscopist
  GIA (Gemological Institute of America)

  Numerous gas bubbles within a pulled synthetic alexandrite. FOV 6.55 mm.
  Photomicrograph: Nathan Renfro.

EIGHTEENTH ANNUAL SINKANKAS SYMPOSIUM
ALEXANDRITE and OTHER COLOR-CHANGE GEMSTONES

Stuart Overlin, Ed.
Photographs by Mia Dixon, Orasa Weldon and Robert Weldon

Specifications: 8.25" x 10.75", digital press, soft cover, perfect binding, 110 pages, full color throughout

Publication Date: June 23, 2022

ISBN: 978-0-9915320-6-3

Available as free PDF download at: independent.academia.edu/SinkankasSymposium

Table of Contents

Dedication and Acknowledgments   i

Contents   1

Speaker and Author Biographies   2

Evan Caplan   6
Alexandrite, Pricing Factors, and the Future Market

William Larson   10
Collecting Color-Change Minerals and Gemstones from World Localities

Çiğdem Lüle   14
Diaspore from Turkey

Sally Eaton-Magaña   18
Color-Change Phenomena in Diamond

Niveet Nagpal   28
Designing with Color-Change Gemstones

Aaron Palke and George R. Rossman    32
Causes of Color in Color-Change Gemstones

Nathan Renfro   40
The Microworld of Alexandrite and Other Color-Change Gems

Stuart Robertson   42
Price Trends of Alexandrite and Other Color-Change Gemstones

Wim Vertriest   48
Overview of the Geology and Mining of Alexandrite

Robert Weldon   52
Gem Photography's Biggest Challenge: Color-Change Gemstones

Ziyin Sun, Aaron C. Palke, Jonathan Muyal, Dino DeGhionno, and Shane F. McClure   60
Geographic Origin Determination of Alexandrite (from the Winter 2019 Gems & Gemology)

Karl Schmetzer   76
Pleochroism and Color Change in Faceted Alexandrite: Influence of Cut and Sample Orientation
(from the Spring 2019 Gems & Gemology)

James E. Shigley and Sheryl Elen   88
Bibliography

ABOUT THE EIGHTEENTH ANNUAL SINKANKAS SYMPOSIUM
– Alexandrite and Other Color-Change Gemstones (VIRTUAL)

Named for one of the most distinguished and influential figures in gemology and mineralogy, the Sinkankas Symposium is an annual event featuring presentations by noted specialists working in diverse gem-related disciplines.

The theme of the Eighteenth Annual Sinkankas Symposium is Alexandrite and Other Color-Change Gemstones. The virtual format of the 2022 symposium featured a menu of 10 pre-recorded 30-minute exclusive presentations available to view on-demand from Monday, April 25, 2022 until Monday, June 13, 2022.

The Sinkankas Symposium has been described as the most important gemological conference in North America by respected authorities on gemstones. Organized by Roger Merk for 13 years (2003–2015), this year's event is co-sponsored by the Gemological Institute of America (GIA), the Geo-Literary Society and the Gemological Society of San Diego. Bill Larson has been a generous supporter and speaker at the event since its inception.