II 



TAB. CCCVII. 



S I L E X Quartzuni, var. 

 Octaedral Calcedony. 



Class 2. Earths, Order 1 . Homogeneous, 

 Gen. 4. Silex. Spec. Quartziim. 



Div. 2. Imitative. Var. Octaedral. 



Syn. Quartz Agathe. Haiiy, 2. 424. 



-= =I31S^g2SJBlSJtI«- 



I was favoured with this fine specimen by Lord Heath- 

 field, who sent it from Beer Alstone in Devonshire. It is 

 a secondary crystallization, having taken the form of songs 

 other substance that was prior to it. It has here taken the 

 place of Fluor or Galsena, most probably Fluor somewhat 

 like that of tab. 26. Some of the casts are extremely neat, 

 others are somewhat hollow, and have Quartz crystals 

 within them. 



C 2 



