 The
Peridot-group consists of two minerals with a rhombic crystal system: Forsterite
und Fayalite.
The minerals have different chemical compositions: Magnesium-silicate (Forterite) and iron-silicate (Fayalite), but together their hardness is 6,5-7 and they are idiochromatic  (
the colour is part of the chemical composition).
Peridot has a bottle-green to dark-green colour and is very longing due to its high refractive index. Peridot is also known as Chrysolite and Olivine. Occurences of peridot: Seberged, Burma, USA and Norway.  |
