Chap. XXXV. ] 
JABALPUR DISTRICT. 
807 
contortion hag occasionally produced a cleavage in the hematite which 
cuts the laininatinn planes at an acute angle, though the cleavage 
usually coincides with the lamination. 
Frequently the hematite contains scattered octahedral magnetite 
crystals varying in size from a pin's head to ^ inch or i inch in diameter, 
and these stand out on the cleavage planes as tiny elevations or pimples 
over which curve hematite films ; the crystals weather out in their typical 
octahedral shape. 
A much less common rock is one composed of bands of very finely 
granular magnetite alternating with jaspery bands, usually whitish or 
brown in colour. 
The siliceous bands that separate the hematite or magnetite layers 
are seen microscopically to consist usually of microcrystalline quartz. 
Sometimes almost cryptocrystalline, and at other times slightly more 
coarsely crystalline ; they may accordingly be termed jasper or jaspery 
quartzite according to their degree of fine-grainedness. The varying 
colours are due to varying impurities. When white the impurities are, 
of course, very small in amount, but when reddish there is usually a cer- 
tain amount of crystalline hematite in tiny scattered grains or of opaque 
red ochre, while the brown jasper associated with the magnetite bands is 
Seen to contain clouds of minute scattered magnetite cubes or octa- 
hedra. The quartz, when in suflficiently large grains, often shows undu- 
latory extinction ; further the rock commonly shows minute quartz 
veins traversing the various bands of jasper and iron-ore indiscrimi- 
nately. 
The hematite bands vary in thickness from mere partings of the 
thickness of a hair in the jasper or quartzite, up to solid ore in layers 
as much as two or three inches thick, with the siliceous bands quite 
subordinate, or even absent, e.g., at Dhanwahi, Dharampura, and 
Gosalpur. This hematite is often very fissile, splitting into thin 
laminae, which are not very friable, but which show a b'ilUant satiny 
lustre, sometimes with fine waves due to minute contortions. At other 
times the hematite is not nearly so fissile, but is more friable, readily 
yielding to the fingers abundant tiny scales of micaceous hematite. 
This latter is more like a schist of micaceous hematite, while the 
former variety more resembles a weU-cleaved slate in structure, and it 
