MANGANESE. 



407 



into a reddish-brown or black globule ; with borax, it forms a violet-coloured glass. When 

 in powder, it is partly soluble in muriatic acid, the residuum assuming a white colour. 



Composition. Specimen from Langhanshytta — Protoxide of manganese 49.04, silica 

 48.00, lime 3.12, magnesia 0.22, oxide of iron, traces {Berzelius). It is probably a true 

 silicate of manganese. Formula MnO.SiOa. 



Specimen from Franklin, New-Jersey — Protoxide of manganese 66.60, silica 29.64, 

 peroxide of iron 0.92, moisture 2.70, alumina a trace (Thomson). This differs much from 

 the preceding. 



Geological Situation. This mineral usually occurs with magnetic iron ore in primitive 

 rocks. 



localities. 



According to Dr. Emmons, silicate of manganese has been found in this State in the coun- 

 ties of Essex and Warren. 



This species occurs at Franklin and Sterling, New-Jersey ; at the former of which, it is 

 associated with magnetic iron ore, franklinite, etc. ; and at the latter, with the red zinc ore, 

 troostite, etc. It is also found in large rolled masses, at Cummington in Massachusetts. 



The Sesquisilicate and Bisilicate of Manganese of Thomson, credited to Franklin in New- 

 Jersey, are perhaps not distinct from this species ; to which also Fowlerite, and according to 

 Beudant, Torrelite should be referred. These minerals, however, differ considerably from 

 the true manganese spar in the proportions of their constituents. 



BABINGTONITE. 



[In compliment to Dr. Babington.] 



Babingtonitc. Levy, Phillips and TTiomson. — Axotomer Augit-Spath. Mohs, 



Description. Colour dark greenish black. It occurs regularly crystallized. The primary 

 Pj ^j p- ^32 form, according to Levy, is a doubly obhque 



prism. Fig. 481. P on M 92° 34' ; P on T 

 88° ; M on T 112° 30'. But it usually crys- 

 tallizes in eight-sided prisms. Fig. 482. g on 

 m 132° 15' ; honm 137° 05' ; hont 155° 25' 

 (Levy). Sometimes the faces m are wanting. 

 Cleavage perfect parallel to P ; less so to t. 

 Fracture imperfect conchoidal. Lustre vitreous. Thin splinters faintly translucent. Hard- 

 ness from 5.5 to 6.0. Specific gravity from 3.40 to 3.50. Before the blowpipe alone, it 

 fuses into a black enamel ; with borax, it gives a transparent violet globule, which in the re- 

 ducing flame becomes bluish green. 



