Serpentine



Serpentine is generally an alteration product of olivine or other mafic minerals. It is frequently found with oxides and often with talc, chlorite, or other Mg-rich silicates. Serpentine may be patchy, scaley, fibrous or blocky. Lizardite, one serpentine variety, typically forms net-like patterns. Chrysotile, another variety, forms sharp skinny needles or fibers.

Important properties:
 ·Appearance and habit - Serpentine may appear in any of a number of guises. It generally has low relief and a grungy appearance. It is a common secondary mineral forming after olivine.
 ·Color - colorless to pale green
 ·Interference colors - Birefringence is low, so interference colors are rarely other than first order whites and greys.

Similar minerals:
 ·Some fibrous amphiboles appear superficially like fibrous serpentine, but they have higher relief and birefringence.
 ·Because serpentine is generally an alteration product, it is often patchy and mixed with other minerals; thus, it may be difficult to identify.


Serpentine and Talc in a Serpentenite (Verde Antique)

This photomicrograph, about 2 mm across, is of a serpentenite from Windsor County, Vermont. Most of the photo shows antigorite, perhaps the most common variety of serpentine (clear to light green color PP, 1st order interference colors XP). The material forming a sickle-shaped patch near the center of the view, showing higher relief and very high order interference colors, is talc. Some patchy magnetite (opaque) can be seen near the right edge.



 

 

 

 

 

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