In other districts the fibre is discoloured (and the value of it consequently much reduced) by the infiltration of water impregnated with the oxide of iron. This is especially the case in the Black Lake district, more particularly on the property of the Anglo-Canadian Company, where the serpentine is a good deal shattered by the action of the weather, or possibly from other causes. This discoloration ceases as a general rule, or at any rate becomes considerably diminished in intensity, in proportion as the containing rock becomes more solid. It is, however, a most serious matter as affecting the character and pecuniary value of these mines. In the case of nearly all the mines there are large quantities of so-called bastard asbestos found in and about them. This is a woody, brittle variety of apparently as yet unformed mineral, for which at present no use seems to have been found; but, judging from the course new applications of the mineral are now taking, there can be little doubt that this inferior article will presently command its price in the market, a use being found for it in some of the many purposes for which coarse pulverized asbestos is found to be applicable. Many other very singular types are also to be seen. Some of the pieces as they lie on the ground, after blasting, have so much the appearance of a wood-cutter's choppings (being, in fact, in the coarse and peculiar grain of the fibre, so like chips of wood), that, if placed side by side with actual chippings from rough timber exposed to the weather in the woods, the one could in no way be distinguished from the other, except of course by handling, when the weight and stony feeling of the asbestos would make the difference at once perceptible. Chrome iron is frequently found, sometimes as at Thetford and South Ham, in very large quantities in close proximity to the asbestos-bearing rock. In the iron, where this is the case, although the stringers of asbestos may be very minute, they will almost certainly be found intersecting the ore, just as we have already seen that the grains and threads of the chrome iron often cut and spoil the fibre of the asbestos. The marketable value of asbestos is determined in the first instance by the colour, coupled with the thickness or width of the fibre in the vein. The colour, it may be said, largely depends upon the locality of the mine, and will be distinguished at once on inspection of the rocky gangue. At Thetford it is of a greenish hue, being there found in the darker coloured serpentine; whilst at Broughton the ore is of a pearly yellowish green, the surrounding rock being mostly of a grey or pale green colour. This difference of colour in the ore, however, in no way affects the value of the mineral, as when crushed out the fibre is mostly of a uniform whiteness.