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Story: Gemstones

Silicified wood and plant material

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When wood and plant material is buried, circulating waters sometimes deposit fine-grained quartz in the cells (silicification), forming a hard rock in which the plant’s original structure can be seen. There has been considerable silicification of plant material in the Coromandel area, producing a silica-rich rock known as Manaia stone.

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Te Ara - The Encyclopedia of New Zealand

Photograph by Alastair McLean

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How to cite this page

Jocelyn Thornton, Gemstones – Quartz, Te Ara – the Encyclopedia of New Zealand, https://teara.govt.nz/en/interactive/5124/silicified-wood-and-plant-material (accessed 4 June 2026).

Story by Jocelyn Thornton, published 2 March 2009.