Chemistry:Pietersite
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.[1]
It was first described in Namibia in 1962[2] and was discovered in Xichuan - in the Henan Province of China - in 1966.[3]
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, crocodolite.[1]
References
- ↑ 1.0 1.1 Kaifan, H.; Heaney, P. (2010). "A MICROSTRUCTURAL STUDY OF PIETERSITE FROM NAMIBIA AND CHINA". Gems and Gemology 46(n.4): 280–286. doi:10.5741/GEMS.46.4.280.
- ↑ Thomas, A. (2008) Gemstones: Properties, Identification and Use. New Holland Publishers, London
- ↑ Zhong H. (1994) Gemstone sources in Henan Province. China Lapidary, Vol. 9, No. 3, pp. 43–46
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