Description:
Quartz was chosen by the geologist Friedrich Mohs to represent grade 7 in his famous scale of hardness dating back to 1825, and which is still valid nowadays. On the small Greek island of Seriphos one can find what are considered to be the most beautiful crystals of green quartz in the world. The colour is due to multiple inclusions of hedenbergite, a green-coloured variety of diopside. |