Regarding the concept of money and currency, a distinction was made between the two, considering money as "something concrete" and currency as "something abstract", in the same process of circulation of the same goods. In fact, "the currency is a standard instrument, related to payment, an instrument for facilitating exchanges, an instrument for accumulating and settling obligations, a general measure of values that enjoys public trust, that bears the state guarantee and which when made of precious metal, guarantees weight and title". Money, generically, refers to all kinds of palpable currency, as a social instrument, as a particular form of social wealth.