is a mineral
aggregate which is formed as a hydrothermal
alteration product of plagioclase feldspar
. It appears very similar to zoisite
with a green or grayish-green color, it has been used as a substitute or simulant for jade
Sassurite is not however recognized as a true mineral because it is a microscopic mixture of several other minerals, zoisite, epidote, sericite, albite or other sodium rich feldspar along with possibly scapolite. The use of microscopic refractive index data and X-ray diffraction patterns are needed to distinguish some saussurite simulants from true jade.
It was named after the Swiss explorer Horace Benedict de Saussure, who discovered it on the slopes of Mont Blanc.