Most of what I know about these cast fakes has been scraped together from various places on the internet. Some information will probably be accurate, some may be less than reliable. The earliest sighting of one of these fakes I have come upon is July 20041, although they may have been around longer, and they may still be churning out new types somewhere. As for where that somewhere may be, several have suggested that these are high quality pressure fakes coming out of Bulgaria that are salted into hoards of genuine coins to increase their number.
These cast fakes are made of silver. I base this conclusion on a post made to the Moneta-L discussion group where Scott Rottinghaus wrote the following about a cast fake Nerva denarius COS II DESIGN III PP he had the misfortune of purchasing: "The weight is correct (maybe just a little on the heavy side) at 3.44 g, and the specific gravity is correct at about 10, indicating good silver."2 For those not familiar with specific gravity, it is a dimensionless measurement of density relative to water. Specific density of some common coinage metals (measured values may vary according to the exact physical state of the metal, as cast, rolled, drawn, because of varying degrees of porosity and of course alloying):
| Metal | Specific gravity |
| Gold | 19.3 |
| Lead | 11.3 |
| Silver | 10.5 |
| Sterling silver (0.925) | 10.2 to 10.3 |
| Copper | 9.0 |
| Tin | 7.3 |
Coin collectors measure the specific gravity of coins they suspect are fake because fakes are sometimes made of metal that does not match the original type. In the case of cast fakes, metals such as lead or tin (which have low melting points) are often used. In the case of the cast fakes shown on this site, the forger has apparently taken the trouble and expense of using silver. There is the alternate possibility that the SG of about was arrived by alloying (e.g. the right amount of lead and tin and you can get a SG anywhere between their respective SGs of 11.3 and 7.3), however based on appearances I conclude that they are silver. Being made of silver doesn't necessarilly mean that the weight of the fakes will be correct, since one would have to get the alloy correct for the type being copied as well as the thickness. For Roman silver denarii mass isn't a very reliable guide to authenticity due to the variance among genuine pieces, but it could be helpful for some of the well-studied Greek series.
