I once received a Mother-of-Pearl casino plaque in the mail as part of a gift. The person who sent it to me knew nothing about chips or collecting... and when I opened the package I found the plaque Scotch taped to a piece of carton; right over the engraved monogrammed pigment. I didn't know how to remove the tape (fast or slow) when I first decided to peel it away... and then I tried to do it slowly. In the process, the pigment stuck to the tape as it was pulled away from the engraving... and it was in sections as large as up to the width of the tape. Under magnification it seemed very "dried painty-looking" to me and was quite durable. I concluded it was oil-based paint (like when you scrape old paint away from a window frame), but what kind; I have no idea.

John