426 Transactions. —Geology. 
Mn0O,, which occurs pure in Pyrolusite, is the most valuable, on account 
of its parting readily with its oxygen to substances capable of combining 
with it, and on this property depends the value of the ore in the generation 
of chlorine for bleaching purposes, the decolourization of glass where sub- 
oxides of this metal form the colouring matter, and also in its recent 
application to the oxidation of phosphorus, etc., in the process of iron 
manufacture 
Manganese, however, also occurs in other forms, which require mention 
as minerals. 
Diallogite, MnC.—The occurrence of this mineral is mentioned by Mr. 
Skey (Geol. Rep. 1870-71, p. 85) associated with Calamine from a claim 
high up the Tararu Creek, Thames, and presented by the manager of 
Russell’s battery. 
He says: “ The Diallogite of this specimen contains a portion of car- 
bonate of lime, but the amount has not yet been ascertained. It is coloured 
with oxide of iron, and crystallized in large rhombohedrons. The carbonate 
of lime forms lustrous transparent crystals attached to the former, but 
always external. These are always well shaped, but comparatively small. 
They are interspersed somewhat rarely with small rock crystals.” I regret 
that I have been unable to find this specimen. 
A massive, flesh-coloured, specimen of this mineral was also collected 
by Dr. Hector, November, 1881, in Makara Valley, where it occurs on 
Mr. Thos. Robinson’s property. 
Rhodonite or Manganese Spar, Mn $i.—The occurrence of this mineral at 
Kawarau and Clutha is mentioned (Jurors’ Rep. N.Z. Ex., 1865, p. 265), 
and at the Pioneer claim, Dunstan (Jurors’ Rep., p. 418), and it has also 
been found in Canterbury and Waiheke. 
Hauerite, Mn'—In a paper read before this Society during the last 
session, I mentioned the occurrence of this mineral, as determined by Mr. 
Skey in rocks from the Wakatipu district, collected by Mr. McKay, and I 
have now to mention its occurrence in certain specimens forwarded by Mr. 
H. P. Washbourn from Collingwood, where it occurs in crystals composed 
of the eube and rhombic dodecahedron. 
Dana only mentions this mineral as occurring at Kaknke is Honea 
in clay with gypsum and sulphur, in a region something like a solfatara, 
but the Mangan-blende or Alabandine which is a subsulphide of —— 
he states, occurs in veins in the gold mines of Nagyag in . 
associated with Tellurium, carbonate of manganese and quartz. It is inter- 
esting, therefore, to note the occurrence 
of ‘Hauerite in crystalline schistose Pe 
rocks, and I was led by this to examine ores from other countries to s°°. - 
: —_— it ever did occur under similar conditions. The result of this 
