Chromium is a silvery metal used to harden steel. In combination with nickel, it is almost indispensable for the production of good armor plate and of stainless steels. It is somewhat expensive (costing $300 a ton in 1941 as ferrochromium, the usual market commodity), but curiously it was one of the few metals produced in any quantity in Japan, at the Hidaka mine. The Allies got most of their chromium from Cuba (177,000 tons a year) and West Africa (390,000 tons a year), but there were significant deposits in the western United States; at Masinloc in the Philippines; in New Caledonia; and at Kolar in India. In general, the deposits take the form of a dark band of chromite at the base of an ophiolite.
Chromium became a limiting resource for the Japanese late in the war, when the Philippine mines were recaptured by the Allies and domestic supplies proved inadequate. The Japanese were forced to replace chromium steels with high-carbon steels, which were a highly unsatisfactory substitute.
References
U.S. Geological Survey (accessed 29 December 2006)
The Pacific War Online Encyclopedia (c) 2007 by Kent G. Budge. Index