M. Dufrenoy's Description of Greenovite. 247 



to be silicate of manganese, and is placed as such in several 

 collections in Paris. 



Greenovite occurs in crystals and in small amorphous cry- 

 stalline masses ; it is of a deep rose colour, and its specific 

 gravity is 3*44. Its hardness is greater than that of fluor 

 spar or phosphate of lime, but it does not scratch glass ; the 

 crystals are splendent, especially the faces M and T ; the ter- 

 minal faces are often dull and tarnished. 



The primary form of the crystal is represented by fig. 1, 

 but other faces have been observed, as shown in fig. 2. 



The measured and partly calculated angles areas follows: — 



This mineral is not acted upon by acids, and is not fusible 

 perse by the blow-pipe ; microcosmic salt denotes the presence 

 of titanium, and with soda it shows manganese. 



To analyse this mineral, M. Cacarrie fused it with five 

 times its weight of bisulphate of potash ; the residue when 

 cold dissolved slowly in water, but almost entirely ; the very 

 small quantity which remained undissolved contained traces 

 of silica, evidently derived from quartz mixed with the green- 

 ovite; the rest was titanic acid. The solution was treated 

 with hydrosulphuric acid, and then supersaturated with am- 

 monia to separate the lime. The residue, composed of tita- 

 nic acid and sulphuret of manganese, was digested in sul- 

 phurous acid, which dissolved the sulphuret. The titanic 

 acid unacted upon was collected, and there was also obtained 

 by ebullition a trace of it from the solution of manganese; an 

 accident prevented the quantity of lime from being determined, 

 but it could not have amounted to one per cent. The pro- 

 portions of the other constituents were ascertained by M. Ca- 

 carrie to be 



Titanic acid 745 



Oxide of manganese... 24*8 



Lime • 99'3 



[The crystal of this substance appears, from the author's 

 statement, to be a doubly oblique prism, but from the sym- 

 metrical "nature of the faces, and the near approximation of 

 the angles, it may possibly turn out to be an oblique rhombic 

 prism. We have not however seen this mineral. — Edit. 

 Phil. Mag.] 



