The Sinkankas Symposium – San Diego County Gems and Minerals


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.  The theme for 2023 will be San Diego County Gems and Minerals. The Nineteenth Annual Sinkankas Symposium, will convene on Saturday, April 22, 2023, at the GIA worldwide headquarters and Robert Mouawad Campus in Carlsbad, California.

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), the annual event is co-sponsored by the Geo-Literary Society and the Gemological Institute of America, which has provided the Symposium venue every year.  Bill Larson has been a generous supporter and speaker at the event since its inception. This year's symposium will be the first in-person event held since 2019. We look forward to seeing you this year.


Saturday, April 22, 2023

8:00 AM – 4:05 PM PDT

GIA (Gemological Institute of America)
World Headquarters and The Robert Mouawad Campus
5345 Armada Drive
Carlsbad, CA 92008



Registration: NOW OPEN (Online Only).

Cost:$125. through April 15, 2023; $135. April 16 through noon, April 19, 2023.

and Breakfast at GIA: 8 – 8:45 AM
Program starts at 8:50 AM sharp.

Contact: Issues with registration should be directed to

Each attendee much be registered under his/her own name (no group registrations under one name) and valid government issued photo ID required at GIA security gate to access the event.

Interest in the Sinkankas Symposium and attendance has grown every year.  Space is limited and is available on a first-come, first-served basis.  Registration for the one-day event includes continental breakfast, lunch and snacks and a copy of the 2023 Sinkankas Symposium Proceedings Volume, which features selected papers on San Diego County Gems and Minerals.

Printed proceedings: One copy of the printed volume is included with one paid registration.
Want more copies or cannot attend the symposium? Printed volumes may be pre-ordered from March 21, 2023, Noon PDT through April 12, 11:59 PM 2023. Online book orders will begin shipping from the print house on May 15, 2023.
Where to order online: (This is the only print run in 2023. There will be no overstock available. Next print run is 2024.)
A free PDF-version of the proceedings will not be available for download until later in 2023 (release date TBD). It will be available only at:




Twelve recognized specialists in fields ranging from geology and mineralogy to history, treatment, cutting and collecting will present on the Gems and Minerals of San Diego County.

Dr. Raquel Alonso-Perez – Tales from the Pala Chief Mine

Bill Larson – The Great Tourmalines of the Pala Gem Mining District

Will Larson – Himalaya Mine Treasures

Brendan Laurs – Geology of San Diego County Pegmatites

Nathan Renfro – Inclusions in Gems and Minerals from San Diego County

Dr. Skip Simmons – Crystallography of Tourmaline

Cal Graeber – San Diego County Mines and Minerals

Meg Berry – Cutting the Gems of San Diego County

Paula Crevoshay – Eureka!

Dr. Aaron Celestian – Using Gems to Illuminate Art and Science

Dr. George R. Rossman and Dr. Aaron Palke – The Causes of Color of the San Diego County Gem Minerals



  •  Gems, Jewelers' Materials, and Ornamental Stones of California, George F. Kunz 

    George F. Kunz
    Gems, Jewelers' Materials, and Ornamental Stones of California

    Kunz describes gemstones of California, gem mines in the state, and pegmatites in San Diego and Riverside counties. This edition is bound in purplish-pink, kunzite-colored cloth.

    GIA Library Holdings »
    Internet Archive »

  •  Rubellite: Tourmaline Rouge, Simmons et al. 

    William B. Simmons, Gloria A. Staebler, David W. Bunk, Alexander U. Falster, Sarah L. Hanson, Karen W. Webber, eds.
    Rubellite: Tourmaline Rouge

    A collection of articles on the history and science of rubellite tourmaline.

    GIA Library Holdings »
    Lithographie »

  •  Rubellite: Tourmaline Rouge, Simmons et al. 

    Michael Menzies and Jeffrey Scovil
    Pegmatites and Their Gem Minerals

    This comprehensive work covers the geology of pegmatites, discussing more than 40 gem minerals.

    GIA Library Holdings »
    Lithographie »

  •  Emeralds and Other Beryls, John Sinkankas 

    John Sinkankas
    Emeralds and Other Beryls

    The definitive work on beryl; the final chapter discusses beryl localities.

    GIA Library Holdings »
    Internet Archive »



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