Mineralpedia Details for Gaidonnayite

Named for Gabrielle Donnay, a former professor and mineralogist at McGill University in Montreal, Quebec, Canada. Gaidonnayite is a rare mineral that occurs in Canada, the United States, Russia, Brazil, and a couple others. At its type locality at Mont Saint-Hilaire, it is found “in miarolitic cavities in nepheline syenite and altered pegmatite dikes in an intrusive alkalic gabbro-syenite complex” and in augite syenite at the mineral’s locality at Narssarssuk in Greenland.  Commonly, Gaidonnayite will fluoresce bright green under shot-wave and long-wave ultraviolet light.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/gaidonnayite.pdf

Formula

Na₂ZrSi₃O₉·2H₂O 

Crystal System

Orthorhombic 

Cleavage

None, None, None 

Color

colorless, white, light lilac 

Streak

white 

Class

Orthorhombic - Pyramidal 

Fracture

Brittle - Conchoidal 

Hardness

5 

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Mindat

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Equant tiny glassy, yellow crystal to about 0.5mm in vug.