Prince Love Symbol - Origin & History

Prince first used a version of the famous 'Love Symbol' in 1982 on the cover of the 1999 album - and it came into prominence in the 1984 film Purple Rain. But where did it come from...?
Somebody was definitely influenced by alchemy symbols as there are exact copies of this logo going back to the 15th century (see below). It is the alchemy symbol for "Copiapite" a mineral.
I thought it was interesting that the alchemy symbol that represents Prince - "cOPIApiTE" contains the word "opiate" which is what lead to the artists untimely death.