422 Transactions.— Geology. 
The ore is found :-— 
1. Massive crystalline.—In bands of a black crystalline character, varying 
in its degrees of coarseness, and in some cases showing distinct planes of 
the octahedron when fractured. No perfect crystals have as yet been 
found. As a rule the crystalline bands have hitherto proved less continuous 
in their character than those next to be described. 
2. Massive amorphous.—In- bands of a brownish-black colour, and afford- 
ing a brown streak. It is softer than the last-mentioned variety, and as a 
rule occurs in larger and better-defined bands of ore, which also appear to 
be more continuous both in length and depth. It is not so valuable an ore 
as the massive crystalline variety, but, on account of its greater extension, 
would probably receive a greater share of attention should works be under- 
taken for its extraction. 
8. Crystalline disseminated—A very interesting example of this ore 
occurs on Little Ben Nevis, consisting of small segregations of chromite 
evenly distributed through a pale-green serpentinous rock. The segrega- 
tions are from 2 inch to } inch diameter, and are spotted through the rock 
with great regularity, giving it the appearance of a conglomerate. When 
found under these conditions the chromite corresponds in physical characters 
with the massive crystalline variety previously described, and the ore- 
bearing rocks appear to run in belts much the same as the regular ore 
bands do, and follow approximately the same course. The surrounding 
rock being soft, a mechanical means of separation for the ore so as to 
increase the percentage of chromic acid should be simple. 
4. Granular disseminated.—In this character Chromite occurs as @ cOn- 
stituent of the rock Dunite, described by Professor Hochstetter (“ New 
Zealand,” 1863, p. 474, Eng. Ed.), as follows :—* It consists of a very 
peculiar kind of rock, of a yellowish-green colour when recently broken but 
turning a rusty-brown on the surface when decomposing. The mass of 
the rock is Olivine, containing fine black grains of chromate of iron inter- 
spersed ; it is distinguished from serpentine, for which it was formerly taken, 
especially by its great hardness and its crystalline structure. I have called 
it Dunite.” These rocks occur in bands, which almost resemble dykes, and 
which are, perhaps, better developed in the Dun Mountain than e 
The quantity of Chromite which occurs in the rock is extremely variable 
from a few dispersed grains to sufficient to form more than half of the 
mass ; and specimens have yielded as much as 44-75 °/,, Crs Os. 
This ore occurs as a 10-foot band in the Dun Mountain Company's 
lease, and in the Roding River Company’s ground a similar band is over 15 
feet in width, and has been opened on vertically for 800 or 400 feet. The 
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