practically
the entire export trade of Canada goes to the United States. Russia
exports nearly all her product to Germany, Austria, United Kingdom,
Belgium, and the Netherlands. Previous to the war the output was largely
controlled by a German syndicate. There is a considerable recent
production in South Africa, which is taken by England and the United
States, and small amounts are produced in Italy, Cyprus, and Australia.

The United States has been a large importer of asbestos, from Canada and
some other sources. Domestic production is relatively insignificant, and
exports depend chiefly on an excess of import. Georgia is the principal
local source. Arizona and California are also producers, their product
being of a higher grade. The United States is the largest manufacturer
of asbestos goods, and exports go to nearly all parts of the world.

So long as the abundant Canadian material is accessible on reasonable
conditions, the United States is about as well situated as if
independent. Some Canadian proposals of restriction during the war led
to a study of other supplies and showed that several deposits, such as
those in Russia and Africa, might compete with the Canadian asbestos.

GEOLOGIC FEATURES

Asbestos consists mostly of magnesium silicate minerals--chrysotile,
anthophyllite, and crocidolite. The term asbestos covers all fibrous
minerals with some tensile strength which are poor conductors and can be
used for heat-protection. Like talc, they are derived principally from
the alteration of olivine, pyroxene, and amphibole,--or more commonly
from serpentine, which itself results from the alteration of these
minerals. Chrysotile is the most common, and because of the length,
fineness, and flexibility of its fibers, enabling it to be spun into
asbestos ropes and fabrics, it is the most valuable. Anthophyllite
fibers, on the other hand, are short, coarse, and brittle, and can be
used only for lower-grade purposes. Crocidolite or blue asbestos is
similar to chrysotile but somewhat inferior in fire-resisting qualities.

Asbestos deposits occur chiefly as veinlets in serpentine rock, which is
itself the alteration of some earlier rock like peridotite. They are
clearly formed in cracks and fissures through the agency of water, but
whether the waters are hot or cold is not apparent. The veinlets have
sometimes been interpreted as fillings of contraction cracks, but more
probably are due to recrystallization of the se