Corsi Collection of Decorative Stones

view of stone 707

Corsi 707, approx. 145 x 73 x 40 mm, © Oxford University Museum of Natural History

OUMNH Number: 707  
Name and quarry location: Quartz chalcedony or more probably flint, locality unknown  
Geological description: Quartz var. chalcedony, coloured by included iron silicates.  
Comments: Nephrite, according to mineralogists, is the fine-grained compact variety of the amphibole series actinolite-tremolite and can be any shade between white and very dark green. It is a particularly tough mineral, one of two known as 'jade'. This specimen, while superficially resembling nephrite, was misidentified by Corsi, and is actually compact fine-grained quartz.  
References:  
Further information:
 


Corsi's classification: Class 13. Feldspars; Species 4. Nephrite  
Corsi's text: 175.1 Pietra nefrite. Marmor aequipondus. Lapides martyrum. Nefrite orientale... non si conosce la cava... giada  

Full entry in English