Pietersite is a variety of Quartz, composed naturally of Tiger’s Eye, Hawk's Eye and Jasper.  The color is deep blue-black, grey and brown.  As shown by the photos looking at the stone from different angle highlights the depth and variation of the colors.  The stone is securely fastened by a sterling silver prong setting. 

Details:

Length is adjustable from 19 inches to 21 inches.

Sterling silver snake chain.

Hand forged sterling silver hook clasp

Pietersite stone is approximately 2 inches, including bail, by 7/8 inch wide and is an irregular triangle shape.