"What is commercially known as asbestos is really a term used to denote a peculiar fibrous form assumed by several distinct minerals, rather than to designate any particular species. Tremolite, actinolite, and other forms of hornblende and serpentine, passing into fibrous varieties, assume the name of asbestos, and the 'Geology of Canada' does not give the mineral as a distinct one, but recognizes it under these different headings. As yet comparatively little asbestos has been found in Canada."
This is sufficient to show how small was the interest, even so recently as that, attaching to this substance in the very country which was so soon to find it taking important rank amongst her natural productions.
That singularly beautiful mineral termed "crocidolite," which displays such sheens and radiances of gold and bronze and green as give it the appearance of satin changed into stone, is nothing more than compressed asbestos. The derivation of its name is not happy. It is said to be from κροκος λιθος, simply crocus-coloured or yellow stone. This is doubtless its general colour, but the finest crocidolite is anything but yellow.
Having heard that there were some fine specimens of asbestos on view at the recent exhibition of the United States products at Earl's Court, I made a journey there specially to see them. In this, however, I was disappointed. There was but one small tray of so-called asbestos (amphibole) on view; and this was of a coarse woody character, very similar in appearance to a sample I had had sent to me recently from California. It was, moreover, of a very poor colour and certainly not of the kind that would readily find a market. I found there, however, a piece of unmistakable chrysotile, grouped amongst a miscellaneous lot of American minerals. The exhibitor at once told me, in reply to my questions, that this was not an American product at all, but that it was a "vegetable matter" found in Canada. He evidently did not know much about it, and said it was not asbestos at all. It was not by any means a fine specimen: it had somewhat the appearance of ordinary Thetford No. 1, though differing slightly in colour. I could get no further information about it, except that it had come from near Ottawa.
At this exhibition I found a splendid display of crocidolite, the sight of which well repaid the visit. I secured a good specimen, but found, on enquiry, that like all the superior qualities of this mineral, it had been brought from Griqualand (South Africa). The sample I secured was of the kind that in the States is called "Tiger-eye," as I presume, from its general tawny-coloured streaky brilliancy. The exhibitor said it was a silicate of iron occurring in asbestos-like fibres. It is of an exceedingly hard, densely compact nature; from its hardness difficult to work, but susceptible of a very high polish. A few years ago it was thought to be a precious stone and accordingly commanded a high price, but recent discoveries of large deposits considerably reduced its value. It is used for a variety of ornamental purposes, for which, from its extreme natural beauty, it is peculiarly adapted. The grain is very fine and in its rough state the fibres are singularly distinct.
There is another very singular substance worth alluding to here, which is often put forward as a substitute for asbestos, and which is said by the manufacturers to be fireproof, frost-proof, vermin-proof, sound-proof, indestructible, and odourless. This is a good deal to say, but is in a great measure true. It is largely used in the United Slates, especially for insulating and other purposes of a like kind. I mean the artificially manufactured material called "Mineral or Slag Wool," which is made from the refuse of the furnaces at ironworks, by, it is said, passing jets of steam through molten slag. This material is manufactured on a somewhat extensive scale by the Western Mineral Wool Company, of Cleveland, Ohio. There is no doubt it is a very useful substance for many of the purposes for which it is recommended, but it can scarcely be expected to compete to any material extent with asbestos from its total want of elasticity and lubricity. Even the finest quality on being crushed between the fingers has a harsh, gritty, metallic feeling, very different from the silky, springy, and greasy feel of the natural fibre.
In connection with this manufactured article, a very curious natural production is called to mind, the origin of which is somewhat similar though brought about by natural causes. I refer to the product of the lava-beds of Hawaii, called by the natives "Pélé's hair." Miss C. F. Gordon Cumming, in her "Fire Fountains of Hawaii," speaks of this as "filaments of stringy brown lava, like spun glass, which lie scattered here and there, having been caught by the wind (when thrown up) in mid-air in a state of perfect fusion, forming fine lava drops, a rain of liquid rock, and so drawn out in silky threads like fine silky hair."
"In fact, this filmy, finely spun glass is known as Pélé's hair—Rauoho o Pélé. It is of a rich olive green or yellowish brown colour—a hint for æsthetic fashions—and is glossy, like the byssus of certain shells, but very brittle to handle. Sometimes when the great fire-fountains toss their spray so high that it flies above the level of the cliffs, the breeze catches it sportively and carries it far away over the island; and the birds line their nests with this silky volcanic hair. Sometimes you can collect handfuls clinging to the rocks to which it has drifted, generally with a pear-shaped drop attached to it." This, it is evident, would crumble and break off short in the fingers, and the mineral wool when handled has just the same gritty brittle feeling one can imagine Pélé's hair to have.
Returning to asbestos, however, its formation or actual origin is at present unknown. In its pure state it is as heavy as the rock in which it is found, so closely are its fine elastic crystalline fibres compressed together. These have a beautiful silky lustre, varying in colour from pure white to a dusky grey or green, sometimes of a yellowish green; the direction of the fibres being transverse to the walls of the vein. The essential point in which it differs from any other known mineral consists in its being at once fibrous and textile. Its quality is determined by the greater or less proportion of silicious or gritty matter with which its fibres are associated. When crushed out from the rock, these fibres, which vie in delicacy with the finest flax or the most beautiful silk, can be corded, spun, and woven into cloth in precisely the same way as any other textile fibre.
Of good quality it is only found in serpentine. One instance of its having been found in quartz is mentioned; but, even in that case we are told, when six feet of the superficial quartz rock had been blasted away, the inevitable serpentine was found cropping through.