The long, silver needle was crafted to look like a sword, while a squat cross with a ruby in its center was affixed atop the sword's hilt. More than an ornament, the pin's sharp tip was coated in a toxin. It was to be used against an enemy if attacked... and use against oneself, if need be.
The Templar pin is primarily used as a Templar badge of office and are primarily worn by Templars who were members of the Inner Sanctum. However, the sharp tip of the Templar pin was also laced with a toxin, allowing the Templar pin to be used as a secretive weapon in cases of self-defense, similarly to how the Assassins have their Hidden Blades.
The Templar Pin's sharp tip can also be used as a tool for assassinations, similarly to the Hidden Blades. This was seen when the Roi des Thunes used his pin to kill Grand Master François de la Serre, plunging the bladed side of the pin into the unsuspecting man's neck and leaving him to bleed to death in Arno Dorian's hands.