GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION OF RADIUM AND URANIUM
The only regions of the world that have as yet produced any large amounts of radium and uranium minerals on a commercial scale are Colorado, Utah and Austria. Cornwall, Australia and Germany have produced a small quantity of these minerals. They are known in small quantities in France and Portugal, and have been reported in India and German East Africa, but in these regions they have not yet become commercially important. They occur sparingly, so far as yet known, and practically as only mineralogical curiosities, in Connecticut, North Carolina, Canada, Norway and many other regions, but may in the future be found in larger quantities.
Minute quantities of radium or its products of disintegration occur in almost all rocks and in the atmosphere, and in the waters of the sea and land, but in such small amounts as to be unavailable as a source of these substances. The source of all radium of commerce at the present time is in the certain few uranium minerals already mentioned. They are found in formations of various geologic ages, from recent superficial deposits to the older crystalline rocks, but show a tendency toward certain modes of occurrence, such as in southwestern Colorado and southeastern Utah as an impregnation in sandstone; in eastern Colorado, Cornwall, Austria and South Australia as one of the gangue minerals in veins of other ores; in North Carolina, Canada, Norway and West Australia in pegmatite or other feldspathic dikes.