Pietersite: Properties, Facts and Photos

What is Pietersite?

Pietersite was discovered in Namibia in 1962 by Sid Pieters, after whom it was later named.

Pietersite is a type of chalcedony with fibres of other minerals that were fractured and re-cemented by silica.

Known for its vibrant swirling patterns, pietersite can occur in various colours, but gold, brown, and blue are the most common. The finest material can be slightly chatoyant.

This optical phenomenon can be seen in several minerals but is best known in tigers eye. In tigers eye, chatoyance occurs in bands, while in pietersite it tends to be far more random or chaotic.

Pietersite is often described as a mix of hawks eye (which is blue tigers eye) and brown tigers eye. However, from a geological perspective, this isn't correct because both are forms of quartz. Pietersite, which is chalcedony, formed under very different conditions.
While pietersite and tigers eye do share many similarities, pietersite formed under very different geological conditions.

The main source of mining pietersite is near the town of Outjo in the Kunene Region of Namibia. The area is also known for deposits of tigers eye and crocidolite. The mineral crocidolite is also known as blue asbestos.

In recent years, there has been some concern regarding the presence of asbestos in pietersite and tigers eye. The danger from asbestos comes when microscopic fibres break away and become airborne and are then breathed in. In pietersite and tigers eye, this isn't possible because the crocidolite is encapsulated deep within the quartz.

In 1966, pietersite was discovered in China's Hunan Province. It was mined during the 1970s and 80s, but flooding forced the mines to close and they have never reopened.  

In 1996, it was reported that pietersite from Namibia was becoming scarce because the mines were nearing depletion.

Both images in our article, which are courtesy of Captain Tenneal, are close-up shots of pietersite.