MANGANESE. 



407 



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

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



Composition. Sj^eci men from Langbanshytta — 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.SiOj. 



Specimen from Franklin, N civ- Jersey — Protoxide of manganese (iG.GO, silica 29.64, 

 peroxide of iron 0.92, moisture 2.70, alumina a trace {Thomson). This diifers 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 Slate 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 Bisilicale of Manganese of Thomson, credited to Franklin in New- 

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

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

 the true manganese spar in the proportions of their constituents. 



Fig. 481. 



Fig. 482. 



BABINGTONITE. 



[In compliment to Dr. Babington.] 



Babingtonitp. Li'rij, Phillips a.m\ Tlwmson. — Axotomcr Avigit-Spatli. Muhs. 



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



form, according to Levy, is a doubly oblique 

 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' ; h on m 137° 05' ; h on t 155° 25' 

 {Levy). Sometimes the faces m arc 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. 



