~~~ head section to the tip gradually become thicker and thickee as it extened to solid Ivory except for the nerve hole and, that is what you see in the central area of an Ivory gambling chip but, not all chips and other final objects of Ivory were alway cut from the ends of the tusk.

I have had chips where the centers were plugged with an approx, diameter of 1/4-inch ivory and, Ivory chip experts as Ken Chopping (a co-author of Seymours book) and Dr. Kenny explain to me that the purpose of the plugs were to fill in the 1/4-inch that was removed in the nerve area so fractures from that area would not spread and eventually crack the chip in half and, the other reason for the plugs was for when they cut and got down just before the tusk became virtually solid; that hollow cavity you see became smaller and almost solid and it was excellent for chips of lesser quality... then I found a whole set with the plugs and everybody was happy, especially Kenny who purchased a lot of them to give to his friends and those who collected Old West and early San Framcisco which, Ken Chopping told me that was the stuff they used on the wooden tables.