This gemstone is quartz with tourmaline inclusions. It's great for protection against negative vibes as the tourmaline absorbs the negative energy before it gets to you, and the quartz emits a positive energy shield. 
 
The stone is wrapped in sterling silver wire to form a one-of-a-kind pendant. The pendant is 5.2cm long in total x 2.2cm wide.  It comes on a 100cm length of grey suede that can be tied or knotted to the desired length. It could be worn on a silver chain or any other cord.