The Sinkankas Symposium 2010


Photograph by Harold and Erica Van Pelt

Named for one of the most distinguished and influential figures in gemology and mineralogy, The Sinkankas Symposium is an annual one-day event featuring presentations by noted specialists working in diverse gem-related disciplines or occupations.  The theme of the Eighth Annual Sinkankas Symposium was Gem Feldspars.

The Sinkankas Symposium has been described as the most important gemological conference in North America by respected authorities on gemstones.  Organized by Roger Merk, the annual event is co-sponsored by the San Diego Mineral & Gem Society and GIA (Gemological Institute of America), which has provided the Sinkankas Symposium venue for the past eight years.  Bill Larson has been a generous supporter and lively speaker at the event since its inception.

Sinkankas Symposium — Gem Feldspars

The 2010 Sinkankas Symposium on Gem Feldspars was held on April 17, 2010, at the Gemological Institute of America (GIA), Carlsbad, California.   Ten speakers presented eleven lectures to an audience of 150 attendees.  Highlights from the program included recent gemological and analytical research on Chinese andesine presented by Shane McClure, Director of the West Coast Identification Services at GIA laboratory in Carlsbad, CA, and Dr. George Rossman, Professor of Mineralogy in the Division of Geology and Planetary Sciences at the California Institute of Technology, Pasadena, CA.

Selected papers prepared for the symposium and articles on Gem Feldspars are available for purchase.  For more information about the papers/To place an order »

Eighth Annual Sinkankas Symposium on Gem Feldspars — Program

Recognized specialists in fields ranging from mineralogy and crystallography to history, treatment, cutting, collecting and selling made presentations on Gem Feldspars, including moonstone, sunstone, labradorite, peristerite and amazonite.  Recent gemological and analytical research on Chinese andesine was also presented.

Speakers and Topics

  • Meg Berry – Tricks to Cutting Gem Feldspars
  • Rock Currier – Amazonite Specimen Production in Colorado and Ethiopia
  • Si Frazier – Spectacular Spectrolite
  • John Koivula – The MicroWorld of Gem Feldspars
  • Bill Larson – World Class Collectable Gem Feldspars
  • Shane McClure – Problem of Copper-Diffused "Chinese" Andesine-Labradorite
  • Dr. George Rossman – Natural and Lab-Induced Color in Feldspars
  • Dr. George Rossman – Chinese Red Andesine
  • Dr. Skip Simmons – Madagascar Gem "Orthoclase" and Crystallography of Gem Feldspars
  • Lisbet Thoresen and Dr. James A. Harrell – Archaeogeomology of Amazonite
  • Bob Weldon, Keynote Speaker – The Many Faces of Feldspar

Feldspar Phenom

Remarkable, outstanding, exceptional—Bill Larson had an extraordinary orthoclase specimen on view at the 2009 Westward Look Show in Tucson.  Dave Wilber brings us on a personalized tour of some highlights in Bill Larson's collection, including a large (we mean really big) transparent yellow orthoclase crystal from Madagascar.  Clip courtesy BlueCap Productions.

  • Sinkankas Symposium
    2014 — Peridot

    The theme for the Twelfth Annual Sinkankas Symposium was Peridot & Uncommon Green Gem Minerals and was held on Saturday, April 5, 2014, at GIA world headquarters in Carlsbad, CA.  The one-day event featured 11 presentations made by nine speakers, with 148 attendees traveling from as far away as Italy and Australia.  Join the mailing list »

  • Richard W. Hughes
    Ruby & Sapphire:
    A Gemologist's Guide

    The most comprehensive book ever written on a single precious stone. 816 pages, 10 lbs. More than 1000 photos, maps, illustrations, with 3500+ references. Publisher: Lotus Gemology.

    US $200.

  • Derek J. Content
    Ruby, Sapphire & Spinel:
    an Archaeological, Textual
    and Cutural Study

    Indispensible 2-volume reference on glyptic from classical antiquity to the modern era. Part I addresses literary sources and extant corpus of glyptic to fill the cultural gap connecting East and West. Part II is the catalogue of the Babar-Content collection. 542 pages, beautiful color photographs by Gonzalo Salcedo. Publisher: Brepols.

    Euro $150,00 excl. tax

    Order direct from the publisher


Andesine – Red-Hot Topic



© 2009– 2023 Lisbet Thoresen. All Rights Reserved.   Editor and Designer: L. Thoresen