Online Encyclopedia of Western Signs and Ideograms Symbols.com

Symbol 5:10

0507

05:10 · A variation of the sign for Neptune, also used to signify arsenic in alchemy and early chemistry. Arsenic was of special importance because of its highly poisonous quality and its effectiveness as a medication for e.g. epilepsy and syphilis, and for raising appetite.
    Other signs used for arsenic are collected under 4240 in Group 42.