The PMSC designation that Howdy gave to "brass core" chips stands for plastic molded, slug core. It can be applied to any kind of chip that has a primarily metal core with plastic molded around it to give it color.

All the chips that were made for casino use had either a solid brass core or what they called a bi-metal core. The bi-metal cores were less expensive and were considerably lighter in weight. Harrahs PMSC chips were the first to be put into play and always had brass cores. Other Northern Nevada clubs also ordered PMSC chips with brass as the material. Several years later, the bi-metal core chips were offered to casinos at lower cost. I believe the Tahoe club Hyatt Regency is the only place to have chips with both materials in use on the tables.

Several California clubs ordered the less expensive bi-metal core chips exclusively. Lucky Chances and Top of the Vine come to mind.

All the odd-ball metal core chips were made in small quantities. A few solid silver and platinum core chips were made as presentation pieces for casino owners. I believe the platinum core chips were made for Bill Harrah. All the others are various experiments by the manufacturer and were never made in large quantity for casino play. These include the brass cores plated in gold or silver, although a few ended up encased in plastic as presentation pieces the casino gave to favored players. Because essentially all the manufacturer's inventory of odd-ball chips eventually ended up in dealer hands, you can still find some of these plated experiments for sale in small quantities. Likewise, you can find un-molded cores from many of the production chips available from a few dealers and it's interesting to add these bare cores to a collection of casino-run finished chips.

The other kind of variation you can find are odd colors and color-mixtures of the molded plastic part of the chip. Some of these were experiments by the manufacturer and some were prototypes to find what color the casino wanted to order. Later after the manufacturer stopped production, odd color chips were made by a molder (not a chip manufacturer) as a custom item for chip collectors. Some of these were solid colors but colors that were never actually in production for casinos. Others were mixtures of colors that had a marbleized appearance, again intended to appeal to collectors and never made for volume use in a casino. These are more akin to the "personal chips" made to order by a few collectors and are not casino-chips at all.

The subject of counterfeit chips made to fool and defraud the casino is an interesting side aspect of PMSC chips. A few foreign makers copied the PMSC design and made high-denomination chips that were actually introduced into play at the casino by cheats. Examination of these by some experts hired by the manufacturers and by the casinos concluded that the cores and the plastic molding were of such high quality that they could not reliably be distinguished from chips ordered by the casino. In several cases, they were detected only when a casino found it had more of a hundred dollar chip in inventory than it had ordered from a manufacturer! Essentially, even chip collectors who look at fine differences in chips could not establish whether a chip was genuine or a fraudulent counterfeit. This situation essentially brought the use of PMSC casino chips to an end, and other technical methods were found to deter counterfeiting. Thus we see various types of embedded electronic devices in the plastic/clay/composite chips that can be used to detect and track real chips as they are offered for play by a gambler. To my knowledge, none of these security methods using embedded devices were employed by makers of PMSC casino chips.