atively our position:

1. Minerals of which our exportable surplus dominates the world
situation:

Copper.
Petroleum has belonged in this class until recently. In
the future imports will be required (see 5 following).

2. Minerals of which our exportable surplus constitutes an important but
not a dominant factor in the world trade:

Cement.
Coal.
Iron and steel.
Phosphates.
Silver.
Sulphur.
Uranium and radium.

3. Minerals of which our exportable surplus is not an important factor
in world trade. Small amounts of most of these minerals have been and
will doubtless continue to be imported because of special grades,
back-haul, or cheaper sources of foreign supply, but these imports are
for the most part not essential as a source of supply:

Aluminum and bauxite.
Arsenic.
Artificial abrasives and emery (except Naxos emery).
Asphalt and bitumen.
Barite.
Bismuth.
Borax.
Bromine.
Building stone (except Italian marble).
Cadmium.
Feldspar.
Fluorspar.
Fuller's earth.
Gold.
Gypsum.
Lead.
Lime.
Magnesite.
Mineral paints (except umber, sienna, and ocher from France and Spain).
Molybdenum.
Pyrite.
Salt (except special classes).
Talc.
Titanium.
Tripoli and diatomaceous earth.
Zinc.

4. Minerals for which the United States must depend almost entirely on
other countries:

Cobalt.
Nickel.
Platinum and metals of the platinum group.
Tin.

5. Minerals for which the United States will depend on foreign sources
for a considerable fraction of the supply:

Antimony.
Asbestos.
Ball clay and kaolin.
Chalk.
Chromite.
Corundum.
Diamond dust and bort.
Garnet.
Graphite.
Grinding pebbles.
Manganese.
Mercury.
Mica.
Monazite.
Naxos emery.
Nitrates.
Petroleum (see below).
Potash.
Precious stones.
Pumice.
Tungsten.
Vanadium.
Zirconium.

In the past the production of petroleum in the United States has
dominated the world petroleum situation; but domestic consumption has
now overtaken production, and unless discoveries of oil come along at a
rapid rate the domestic deficiency seems likely to increase, with
corresponding increase in our dependence on foreign sources (see pp.
128-132).

Some of the minerals of this last class, such as potash, manganese, and
chromite were developed under war conditions in the United States to
such an extent as to materially lessen the demand