A pentacle[Footnote 1] is a symbol of order with five points and five sides contained within a circle, most often in the form of a pendant. Harry Dresden wears one that he got from his mother Margaret LeFay.
According to Harry Dresden, a pentacle has a shape of a five-pointed star included in a circle. The star has also five sides representing the forces of air, earth, water, fire, and spirit. If the points touch the outer ring, it representing the forces of magic bound within human control; power balanced by restraint. If the points are outside the circle, it is a symbol of disorder.
In the seriesEdit
In Small Favor, Karrin Murphy calls Harry Dresden to a crime scene in which a burning building had the whole front taken off. On the back wall of the building, Dresden finds a sigil painted in blood looking similar to a pentacle. Dresden explains to her what a pentacle is the difference with a pentagram. At this point, Dresden is uncertain what it means since a symbol can have numerous meanings, but he's working on it.
Dresden shows Murphy that the points of the star on his pentacle touch the outer ring while the points of the star in the sigil they found on the wall go outside the circle; according to him, it's uncomfortably like a combination of a pentacle and an anarchy symbol - magic unrestrained.
In Changes, the Leanansidhe passes on to Harry Dresden the small pentagon-shaped ruby that Margaret LeFay left for him, which contains her considerable knowledge of the Ways in Nevernever. Dresden hurriedly attaches it to center of his pentacle pendant, also his mother's. He plans to use it to rescue Maggie from Arriana Ortega, the Red King and the Bloodline curse.