Currently I'm studying accountancy, so the concept of monetary value has suddenly become important to me. I had pondered it in the past, but not to a great exte

Currently I'm studying accountancy, so the concept of monetary value has suddenly become important to me. I had pondered it in the past, but not to a great extent. A currency only has value because we, as a society, decide that it does. As we've seen, it also needs to be stable, portable and non-toxic. The second sentence contradicts the first. Portability is very important to the effectiveness of a currency, especially in times past when our modern communication methods did not exist. Currency represents an agreement as well as a quantitative value. The ten pound note currently in my wallet is a liability that the Bank of England owes to me when demanded. This is far more convenient than having to call up the Bank of England and demand a portion of their liability every time I go and buy a pack of ciggies (another viable currency, if you are presently incarcerated). A similar argument applies to another whole class of elements, the radioactive ones: you don't want your cash to give you cancer. Regarding Uranium 238, this has a very long half life (roughly the same as the age of the Earth) and it is an alpha-emitter. Radioactive effects of alpha-emitters are usually only toxic if ingested or inhaled, whereas a strong beta-emitter can burn your skin in sufficient amounts. The chemical toxicity of Uranium is a far more serious issue. If the potential radio-currency is highly radioactive, it would lose its value very quickly. Of the four main decay series, three result in lead.