Planetary Symbols

The planetary symbols of the Sailor Senshi are usually the astronomical symbol of their planet.

Description
It would appear on their forehead when they awakened to their true destiny as Sailor Senshi, or when they performed feats of great power. It was also used as a motif on their magical items, such as their transformation pens.

Sailor Moon's planetary symbol, the golden crescent moon, was worn by all members of the Moon Kingdom. Sailor V, as the decoy Moon Princess, also used the crescent-moon mark.

Nemesis' planetary symbol, being the opposite of the Moon Kingdom, was the upside-down black crescent moon on the foreheads.

Trivia

 * Although Tuxedo Mask was considered to represent the planet Earth, he never uses its symbol