Does your chip look exactly like the one below? (Be sure to compare the mold--that is the impressions in the clay around the center. If your mold is different, it's a different chip than I'm about to describe.)

If so, it is referred to as N4075 in The Chip Rack. The Chip Rack puts its value at $600-$699.
It is called the 8th issue in the 3rd edition of the Official U.S. Casino Chip Price Guide, with a rarity of R-7 and value of $900 for Average, $2,000 for Slightly Used and $3,000 for New.

One like it sold at the auction held at the Casino Chip & Token Collectors Club convention in June for $600.