21 



TAB. CXIL 



ilNCUM sulplmreum ; Var. cubicum, 

 Cubical Sulphur et of Zinc y or Blend, 



Class 3. Metals. Order 1. Homogeneous. 

 Gen. 6. Zinc. Spec. 2. Sulphuret of. 



Div. 1. Crystallized. 



1 he rectangular or cubical formation of these crystals of 



O J 



Blend is, I believe, quite new to the Mineralogical World. 

 Two specimens have been sent from Cornwall, one marked 

 from Tincroft, the other from Polgooth, and were probably 

 from the stores of a miner who did not exactly know from 

 what mine they were brought. These luckily came into the 

 hands of my kind friend A. MacLeay, Esq., Secretary to 

 the Linnean Society, who was so good as to give me the 

 one here figured. 



The cubes of this specimen curiously show the diagonal 

 stride, and indicate the accumulation of plates upon the te- 

 traedrons, or more common modification*. See these more 

 plainly marked on the upper right hand geometrical figure. 



* It may not be amiss to remark that several other substances are striated 

 in the direction of their principal modification; as Fluor, whose primitive is 

 an octaedron, but is generally striated in the direction of a cube; Oxide of 

 Tin, Sec. This arrangement of striae is.apt to mislead inexperienced observers, 



