If it's not too late to add to the bibliography/discussion of ceramic gaming
pieces:
twelve disks were recovered at the site of Ventura Mission (California), in a
mixed trash deposit containing evidence of the prehistoric, Mission, Chinese,
and early Colonial occupations.  They range in size from 1.3 to 2.8 cm.
Materials are Chinese Export Canton (1 ex.); San Elizario Polychrome
(Majolica - 1);  hand painted polychrome porcelain (1); plain porcelain (1);
mulberry transfer print on earthenware (1);  whiteware with low molded relief
(1); undecorated whiteware (6, one with illegible portion of impressed mark).
 All of these were carefully chipped to circular.

A 13th example, unfinished and broken, suggests a possible alternative
interpretation as blanks for buttons.  This has been carefully ground into
shape, made from a blue transfer printed earthenware hollow vessel form
printed on both sides.  One perforation has been drilled clear through the
item, and a second hole is profiled through the break.

Mean date of the identified whole vessels in the feature was 1861.4.  The
materials are reported in "The Chaging Faces of Mail Street: Ventura Mission
Plaza Archaeological Project"  (1976).

Roberta Greenwood