The spear of Mars ♂ is an astrological and astronomical symbol representing the planet Mars.
In Mesopotamia, the planet Mars was associated with the god of war and pestilence Nergal. The ancient Greeks connected the planet with their god of war, Ares, and Romans identified it with Mars, their god of war and masculinity (as well as guardian of soldiers and farmers). In alchemical tradition, Mars was associated with iron. In Romance languages, the word for Tuesday originates from Latin Martis dies, i.e. “day of Mars” (mardi, martedì, martes, marți). In Germanic laguages, this day became connected with god Týr or Tiwaz (Dienstag, dinsdag, tirsdag, tisdag and so on).
The arrow and a circle in the current symbol ♂ represent spear and shield, respectively. In biology, medicine and genealogy, ♂ symbolises the male sex; in sociology and gender politics, the male gender.
More photos of sea glass @ Shutterstock.