TWO NEW MINERALS. 167 



to the following one (liebigite) with less water, and sulphuric 

 instead of carbonic acid, the acid being derived from the de- 

 composition of the pyrites associated with the pitchblende. 

 Its composition is represented by li S+Oa C-f-15H. 



This mineral is called medjidite in honor of the reigning 

 Sultan of Turkey, Abdul-Medjid, who exhibits a most decided 

 patronage of both the arts and sciences, certainly much more 

 than any of his predecessors. 



Liebigite (Carbonate of Uranium and Lime). 



This mineral is not found crystallized, but occurs in the form 

 of a mammillary concretion, having an apparent cleavage in 

 one direction. It is of a beautiful apple-green color, transpa- 

 rent, with a vitreous fracture. Hardness between 2 and 2.5 : 

 specific gravity not ascertained. 



Chemical Characters. — The mineral admits of ready separa- 

 tion from the pitchblende, and owing to its color and trans- 

 parency is easily freed from the smallest portion of foreign 

 matter. Heated gently, it loses water, acquiring a yellowish- 

 gray color ; heated to redness, it blackens without fusing, and on 

 cooling returns to an orange-red color ; heated strongly before the 

 blowpipe, with or without charcoal, it blackens, and on cooling 

 remains so ; with borax it gives a yellow glass in the oxidizing 

 and a green glass in the inner flame. Its property of black- 

 ening when heated to redness, and assuming an orange-red 

 color on cooling, made me suppose that it might contain van- 

 adic acid ; but, as will be seen a little farther on, its reactions 

 proved this not to be the case. As yet I believe that this prop- 

 erty is not known to belong to any other natural combination 

 of uranium. 



The mineral dissolves readily in dilute acids and with violent 

 effervescence, affording a yellow solution that gives a yellow 

 precipitate with ammonia and its carbonate ; bxit the latter in 

 excess redissolves most of the precipitate, and what remains 

 is found to be carbonate of lime. The carbonate of ammonia 

 solution when boiled redeposits a yellow precipitate. In a 

 neutral solution sulphureted hydrogen produces no precipitate, 

 but the hydrosulphate of ammonia furnishes one of a brown 

 color, and the ferro-cyanuret of potassium one that is reddish- 

 brown. 



