Not an expensive chip, but last year I wrote an article about my search to find the origin of a light green $5 chip with the initials "C&C". I never knew there was another denomination until one of the dealers recognized my name and asked me about the article, then pointed out this blue $1 chip he had for sale. I snapped it up and will add an addendum to my article sometime in the near future. Finding this was a very pleasant surprise.

The article can be read at the following link:

http://www.markcotton.com/c&c.htm

And here's the chip that I brought home: