Pietersite is a commercial term for a variety of the mineral chalcedony. Originating from Namibia and China, where it is mined for use as a decorative stone due to its chaotic chatoyancy and brecciated structure.
Ranging in colour from brownish-red, to blue-grey, and chatoyant yellow. The Chinese variety are predominantly a reddish-brown, with regions of chatoyant blue and yellow. The Namibian variety are less varied, being predominantly a chatoyant blue-grey, with less common reddish-browns and yellows.
It was first described in Namibia in 1962Thomas, A. (2008) Gemstones: Properties, Identification and Use. New Holland Publishers, London and was discovered in Xichuan - in the Henan Province of China - in 1966.Zhong H. (1994) Gemstone sources in Henan Province. China Lapidary, Vol. 9, No. 3, pp. 43–46
Pietersite is often inaccurately described as a brecciated form of tiger's-eye or hawk's-eye, due to the brecciated texture containing chatoyant material. However, while they are similar mineralogically, pietersite is not a brecciated form of either. Instead, the chatoyancy is due to a shared mineral, crocidolite.
References
External links Gemdat.org Mindat.org