they look like alchemical symbols to me.
I at first thought sagittarius or jupiter but that's just because i studied astrology in middle school :P
#1 looks like iron (or sag)
#2 is tin (or jupiter)
#3 is crystal
#4 i'm not sure..it could be a variation of lead, steel, borax, or decomposure...


or I could just be a huge geek.