MANGANESE. 191 
Triplite. 
Trimetric. Usually massive, with cleavage in three di- 
rections. Color blackish brown. Streak yellowish gray. 
Lustre resinous ; nearlyeor quite opaque. H.=5-5°5. G.= 
34-38. 
Composition. (Mn,Fe),0,P.+RF,, affording about 30 
per cent. of manganese protoxide, 8 of fluorine. Fuses 
easily to a black magnetic globule. B.B. imparts a violet 
color to the hot borax bead. Dissolves in hydrochloric 
acid. 
Obs. From Limoges in France. Rather abundant at 
Washington, Conn., and sparingly found at Sterling, Mass. 
Heterosite, Aliuaudite, Pseudotriplite, are regarded as results of 
alteration, either of triphyline or of triplite. 
Triploidite. A manganese-iron phosphate like triplite, but having 
the fluorine replaced by the elements of water. From Redding, Conn. 
Dickinsonite. An oil-green to olive-green manganese-iron-calcium 
phesphate. From Redding, Conn. 
Reddingite. A rose-pink hydrous manganese-iron phosphate. Mn, 
O, P,+38 aq, isomorphous with scorcdite and strengite. Redding, Ct. 
Fairfieldite, hydrous manganese-calcium phosphate. Ibid. 
Hureaulite. Rose-colored to brownish-orange hydrous manganese- 
iron phosphate. From Hureaux, France. 
Rhodochrosite.—Manganese Carbonate. 
Rhombohedral. AA R= 166° 51’; like calcite in hav- 
ing three easy cleavages, and in lustre. Color rose-red. 
MW = 39-4'5. G.=3'4-3°%. 
Composition. Mn O,C=Carbonic acid 386, manganese 
protoxide 61°4=100. Part of the manganese often replaced 
by calcium, magnesium or iron. 
Obs. From Saxony, ‘Transylvania, the Hartz, Ireland ; 
Mine Hill, New Jersey ; Redding, Conn.; Austin, Nevada ; 
Placentia Bay, Newfoundland. 
Rhodonite. Amanganese silicate. See p. 247. 
General Remarks. Manganese is never used in the arts in the pure 
state ; but as an oxide it is largely employed in bleaching. The im- 
portance of the ore for this purpose depends on the oxygen it con- 
tains, and the facility with which this gas is given up. As the ores 
are often impure, it is important to ascertain their value in this re- 
spect. This is most readily done by heating gently the pulverized ore 
with hydrochloric acid, and ascertaining the amount of chlorine given 
off. The chlorine may be made to pass into milk of lime, to form a 
chloride, and the value of the chloride then tested according to the 
usual modes. The amount of chlorine derived from a given quantity 
