TAB. CCCIII. 



CUPRUM arseniatum. 

 Arseniate of Copper, 



Class 3. Metals. Order 1. Homogeneous. 



Gen. Copper. Spec. Arseniate of. 



In addition to our former figures of Arseniate of Copper, 

 tabs. 168, 169, 170, I am happy to figure these curious 

 varieties, not merely because they are rare, but as examples 

 that are of more consequence, as they will explain many 

 groups of this substance that are scarcely, if at all, under- 

 stood. The present rotate specimens, if I may so call 

 them, are, as it were, a congeries formed of the truncated 

 triedral column, chiefly like the left hand bottom outline. 

 The other outline shows, by the small dots, that one of the 

 solid angles is sometimes replaced by a new face, which 

 would give it a wedge form, very applicable to the rotate 

 formation of the upper specimen : they, however, seem 

 more perfect columns, and are placed among each other 

 somewhat upon the principle of the Galena in tab. 131. 

 The middle outline shows the columnar sides and the tri- 

 angular ends, nearly as they appear when magnified. Some 

 are very small, and others larger and more irregular, some- 

 what approaching the broad faces, and even the mackles, 

 as in the next figure. 



