51 



TAB. CXXVIII. 



CALX carbonata; var. dodecaedra. 

 Dodecaedral crystallized Carbonate of Lime. 



Class 2. Earths. Order I. Homogeneous. 

 Gen. I. Lime. Spec. 5. Carbonate of Lime. 



Div. 1. Crystallized. 



Syn. Chaux carbonatee bisunitaire ? £. Haiiy, 2. 142. 



!!5ome Carbonates of Lime, with regard to their crystalli- 

 zation, are not uncommon. This however is of the scarce 

 kindj and was it not for the manner in which the modifica- 

 tion appears to be formed, it might, under the common 

 idea of its being a rhomboidal dodecaedron, be esteemed as 

 a Garnet, or some other substance that commonly exhibits 

 that figure. — The fracture of Carbonate of Lime is very ap- 

 parent in it; as well as the shapes of the primitive rhombs, 

 which will be found to agree with the figure of the fracture ; 

 and are placed in such a manner as to form the dodecaedron. 

 Thus we find the column is formed of laminae placed on 

 the face of the rhomb decreasing from the lateral edges. Its 

 termination is at one or both ends, clearly in the form of 

 the equiaxe. — The middle figure expresses this with the 

 fracture, which is mostly on the edges. The whole is a 

 sort of inverse crystal ; the column being, as it were, 

 formed contrary to the usual custom. 



The specimen from which this figure was taken was lent 

 us by our friend Mr. Rich. Phillips, who brought it from 

 the North. 



f 2 



