Pentacle

A Pentacle is a symbol of order with five points and five sides contained within a circle. The term pentacle most often refers to a pendant. Harry Dresden wears one that he got from his mother Margaret Gwendolyn LeFay.

Description
Per Harry Dresden: it's a symbol of order with five points and five sides representing the forces of air, earth, water, fire, and spirit. It is contained within a circle, the points touching the outer ring. It represents the forces of magic bound within human control. Power balanced with restraint.

In the Series
In Small Favor, Karrin Murphy calls Harry to a crime scene in which a burning building had the whole front taken off. On the back wall of hte building, Harry finds a sigil painted in blood looking similar to a pentacle. Harry explains what a Pentacle is to Murphy and how a pentagram is different. At this point Harry is uncertain what it means since a symbol can have varrying meanings, but he's working on it.

In Changes, Lea passed on the small pentagon-shaped ruby that his mother, Margaret LeFay left for him when he was ready. It contains the sum of her knowledge of The Ways in Nevernever, which was considerable. Harry hurriedly attaches it to center of his pentacle pendant, also left to him by his mother. He plans to use it to rescue Maggie from Arriana Ortega, the Red King and the Bloodline Curse.

Pentacle vs. Pentagram
Harry 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. Harry says that it's uncomfortably like a combination of a pentacle and an anarchy symbol. — Magic unrestrained.

External References

 * Pentacle — Wikipedia


 * Pentagram — Wikipedia
 * Difference between a Pentacle and a Pentagram — Wiki Answers
 * Pentacle vs. Pentagram  — Yahoo Answers
 * Pentacle vs. Pentagram — Wiccan Information blog
 * Frequently Confused Symbols —Religious Tolerance