Wairakite - Ca(Si4Al2)O12 * 2H2OF

Wairakite was first discovered by Steiner in 1955 in rocks ejected by steam from drill holes in Wairakei geothermal field (New Zeland). Wairakite is a zeolite mineral with an analcime structure. Except for a few deep-sea occurrences, wairakite comes from environments that have or had temperatures above 200°C. Wairakite is common in active or inactive geothermal systems and in some low-grade metamorphic aureoles, especially where associated with epizonal plutons.

Optical properties:
Form: From fibrous to subhedral trapezohedral crystals, also as incrustation.
Color: Colourless.
Relief: Moderate.
Birefringence: Very low.

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Snow-white wairakite crystals. Toi Mine, Honshu Island, Japan


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White Wairakite crystals. Lake Tauppo, Wairakei geothermal field, New Zeland.




Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Optical Mineralogy : The Nonopaque Minerals by Phillips / Griffen
• E. WM. Heinrich (1956): Microscopic Petrografy. Mcgraw-hill book company,inc


Photo
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Aegirine (green) crystals surrounded by wairakite crystals in a syenite from Mont Saint-Hilaire, Canada. PPL image, 2x (Field of view = 7mm)
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Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 2x (Field of view = 7mm)
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Aegirine (green) crystals surrounded by wairakite crystals in a syenite from Mont Saint-Hilaire, Canada. PPL image, 2x (Field of view = 7mm)
wairakite(4).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 2x (Field of view = 7mm)
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Aegirine (green) crystals surrounded by wairakite crystals in a syenite from Mont Saint-Hilaire, Canada. PPL image, 2x (Field of view = 7mm)
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Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 2x (Field of view = 7mm)
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Aegirine (green) crystals surrounded by wairakite crystals in a syenite from Mont Saint-Hilaire, Canada. PPL image, 2x (Field of view = 7mm)
wairakite(13).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 2x (Field of view = 7mm)
wairakite(11).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 2x (Field of view = 7mm)
wairakite(14).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
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Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
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Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(28).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(29).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(31).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(20).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(22).jpg

Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
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Aegirine crystals surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(23).jpg

Aegirine (green) crystal surrounded by wairakite crystals in a syenite from Mont Saint-Hilaire, Canada. PPL image, 10x (Field of view = 2mm)
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Aegirine (green) crystal surrounded by wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
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Wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
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Wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
wairakite(27).jpg

Wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)
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Wairakite crystals (with gray-white birefringence) in a syenite from Mont Saint-Hilaire, Canada. XPL image, 10x (Field of view = 2mm)