Pietersite is a rare dark gray or reddish breccia aggregate (fragments embedded in a matrix), of Hawks Eye and Tigers Eye.
 
Pietersite from Namibia was first reported in 1962 by Sid Pieters, who named it in his father's honor. The term "Pietersite" is now used as a general term to describe brecciated Tigers Eye.
 
Pietersite is characterized by distinctive swirls or streaks of gold or orange, from Crocidolite inclusions within a microcrystalline silica host. Crocidolite is the material that creates the chatoyancy in Tigers Eye.
 
The inclusions in Pietersite show unpredictable chatoyancy when polished. The inclusions are arranged in parallel lines and give the appearance of a continuous line in Tigers Eye.