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
| 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. |