This green rock is sold under the deceptive trade names »African Jade« or »Malachite Jade«.
Gemological examinations of the EPI-Lab showed that the physical properties of the stone differ significantly from those of the recognized Jade minerals jadeite and nephrite. The microscope revealed a granular rock consisting of dark to light green as well as colorless minerals. To rule out that this stone contains Jade minerals in minor quantities, Raman spectroscopy, EDX and thin section analysis we performed.
We found a lot of colorless quartz which is the main constituent of this stone. Two green minerals could be identified: light green diopside and a dark green mineral of the amphibole group. The black banding originates in the presence of ores like pyrite and goethite. The latter was probably formed by the conversion from hematite or magnetite.
Conclusion:
This stone has nothing to do with the known Jade minerals jadeite or nephrite. It is a green member of the quartzite rock group. The correct name is: Diopside-Quartzite.
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