There are plenty of spells from various witchcraft traditions that use coins, especially silver coins. Even in Hoodoo and Conjure – which are uniquely American traditions borne of the union of European and African folk magic, with a healthy dose of Native American lore for seasoning – you will find that the “Mercury Dime” is favoured. This is a ten-cent coin that depicts the winged head of Liberty, but it is easy to see why it was mistaken for the Roman God Mercury. It was minted between 1916 and 1945, and is used as a good luck charm or for prosperity, especially by gamblers. Mercury dimes minted in a Leap Year are said to carry double the luck. For those of a British persuasion, the coin of choice is the silver sixpence, once ubiquitous as the token placed in every Christmas pudding, to give luck to the one who found it — providing they didn’t swallow it, of course.
There are many things about the sixpence that makes it particularly valuable to the crafter, especially in modern times. Firstly, as a coin, it has been around for a very long time. The first sixpence was struck for Edward VI in 1551, and it was legal tender until decimalization in 1971. It was also the last coin to be made of silver — until 1920 the sixpence was sterling silver, and in that year it was reduced to 50% silver. It was not until 1946 that the Treasury switched to cupro-nickel. So a pre-1946 coin has both the weight of history and real silver in its makeup. This made it especially valuable for spellcrafting, but the final clincher is its value, sixpence for the six arms of the Hex Star.
Modern crafters have the additional advantage that it has been withdrawn from circulation. It is no longer legal tender in this realm, making it “legal tender” in the next world instead. The old custom was to bend a coin, rendering it useless for mundane purposes, but now all sixpences come ready to use in the realms beyond this one.