Saussurite

Saussurite is a mineral aggregate which is formed as a hydrothermal alteration product of plagioclase feldspar.It was named after the Swiss explorer Horace Benedict de Saussure, who discovered it on the slopes of Mont Blanc.

It’s a common alteration product of plagioclase and its require addition of water, that change An-component to epidote (Zoisite or Clinozoisite), ancd the residual plagioclase is left as albite. Saussurite is formed under the same condition that characterize the greenschist or other low-P facies. Sericite and calcite often accompany Saussurite.

Saussurite is not however recognized as a true mineral because it is a microscopic mixture of several other minerals, zoisite, epidote, sericite, albite.

Bibliography



• Deer, W.A., Howie, R.A., Zussman, J. (1998) Rock-forming Minerals.
• Nesse, William D., 1986, Introduction to Optical Mineralogy: New York, Oxford University Press
Mindat



Photo
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Plagioclase altered by Saussurite. XPL image, 10x (Field of view = 2mm)
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Plagioclase altered by Saussurite. XPL image, 10x (Field of view = 2mm)
ssaussutitizzazionee(4).jpg

Plagioclase altered by Saussurite. PPL image, 10x (Field of view = 2mm)
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Plagioclase altered by Saussurite. XPL image, 10x (Field of view = 2mm)
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Plagioclase altered by Saussurite. PPL image, 10x (Field of view = 2mm)
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Plagioclase altered by Saussurite. XPL image, 10x (Field of view = 2mm)
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Plagioclase altered by Saussurite. PPL image, 10x (Field of view = 2mm)
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Plagioclase altered by Saussurite. XPL image, 10x (Field of view = 2mm)
plgalteeratoo(4).jpg

Plagioclase altered by Saussurite. PPL image, 10x (Field of view = 2mm)
plgalteeratoo(3).jpg

Plagioclase altered by Saussurite. XPL image, 10x (Field of view = 2mm)