"The theory of how it differs has been developed in more detail than you might care to listen to, particularly if you hold Alchemy to be nonsensical," said Fatio. "It has to do with how the particles—the atoms—of gold are composed, one to the next, to form networks, and networks of networks, et cetera, et cetera, and what occupies, or may pass into, the holes in the said nets. Suffice it to say that the Solomonic Gold, though it looks the same, is slightly heavier than mundane gold. And so even those who know nothing of the Art may recognize a sample of this Gold as extraordinary merely by weighing it, and computing its density. A large trove of such gold was found in Mexico some years ago and brought back to Spain by the ex-Viceroy, who intended to sell it to Lothar von Hacklheber, but—"