The pentacle has always been regarded as a strongly protective emblem. In medieval times it was used to ward off evil spirits and magicians still use it to banish unwanted forces and energies. Many Wiccans and other Pagans use the pentacle as a protective seal or as a symbol of their faith and place in the Universe.

Crescent Moon Symbolism
The crescent is one of the oldest symbols known to humanity, dating back to the earliest Mesopotamian civilizations.  The crescent moon symbolizes change and flux, the eternal cycles of life, lunar deities and lunar magic. Some magickal associations of the moon include fertility, spirituality, wisdom, psychic perception, dreams, and contemplation.