Serpentine 500 gr Raw Minerals Stones Rocks Collecting

Lot 500 gr Serpentino 13 Pieces Raw Minerals Stones Rocks for Collection.
Each stone: 20-60 gr, cm 3-5.
The lot is just that of the photo.
Also available in single piece, at this link.

Serpentine is a group of minerals common in mafic and ultramafic metamorphic rocks. Serpentine means the polymorphic modifications of the compound Mg3(Si2O5)(OH)4.
Serpentine is a hydrated phyllosilicate with a trioctahedral structure which crystallizes in the monoclinic and rhombic systems of the trimetric group.
The most common coils are:
- lizardite (in pseudo-hexagonal flakes or compact aggregates with planar arrangement of the layers);
- chrysotile (in fibrous aggregates such as asbestos with a cylindrical arrangement of the layers);
- antigorite (in rectangular flakes and in compact masses with planar morphology by pseudogemination).
Serpentine is the transformation product of pyroxene and/or olivine by serpentinization of peridotite and is the fundamental constituent of serpentinite.
It is observed in the areas of denudation of the sub-oceanic mantle and in the orogenic zones where it generally emerges in the ophiolites.
Often the serpentine is present in very minute particles and it is not possible to distinguish the varieties except through investigations with X-rays or electronic microprobe.