For an accurate description/history of Mother-of-Pearl Game Counters, you might want to read Derek Cowan's 30-page-Chapter in:

Antique Gambling Chips - Revised Edition

Additional information on Derek's separate work is available by contacting:

Dale Seymour
Past Pleasures
P.O. Box 50863
Palo Alto, CA 94303

Afterwards, you will know everything there is to know about these little works of art.

JB