Jeff:

ASM Chips (American Standard Molding) uses brass flakes in their chips. Their weight comes in at around 9 to 9.5 grams each. They sell online at Pokerchipsonline.com. They make custom chips and have a few home sets. They have several molds. H-mold, horsehead mold and "American" mold chips are usually ASM's.

I'm not sure which playable casino set would be the heaviest, but will drop some of my samples on a gram scale tonight after work for you and send results. Bud Jones "coin-center" chips weigh about 12.5 grams each, but are not what you're looking for. Paulson "classic" or "World Top Hat and Cane" retail chips are real clay and have edge spots, and are around 9 or 9.5 grams.

You may have a tough time finding a chip as heavy as that old one. Paulson chips made "back in the day" for Vegas casinos were composed of up to 40 percent lead, and are from a time when nobody expected you to eat your casino chip and call a lawyer. The company's gone through several incarnations, and has reduced the amount of lead in their recipe so that chips made in the last 10 years have less lead than what is permitted in drinking water.