Although there is a wide diversity in the forms of the deposits and the nature of enclosing rocks, stibnite shows a distinct tendency to form replacements in limestone. The chief gangue minerals are quartz and calcite. Of other sulphides pyrite is the commonest, but cinnabar, realgar, chalcopyrite, galena, and sphalerite are often present as accessories. A characteristic feature of stibnite deposits is the relative scarcity of other sulphides; and it is equally true that important sulphide deposits of other metals rarely contain stibnite. An exception to the general rule is cinnabar, the sulphide of mercury, which is a characteristic mineral of certain stibnite veins. Likewise stibnite is one of the minerals most frequently associated with cinnabar deposits.
Several of the most important antimony districts owe their production of that metal to the presence of recoverable amounts of gold. This is true of certain French, Hungarian, Australian, and South African deposits.
GEOGRAPHICAL DISTRIBUTION, AND POLITICAL AND COMMERCIAL CONTROL
Although antimony has been produced at times from a great many localities in the world, in only a few countries have deposits been developed to an important extent commercially. Under normal conditions of consumption the potential supply of antimony ore is far in excess of the demand. Consequently only those deposits that can be cheaply worked and are favorably situated with regard to markets, or contain appreciable amounts of other minerals, principally gold, have been extensively exploited.
The antimony-producing countries of the world may be divided into three groups as follows:
1. Chief producing countries in order of importance: China, France and Algeria, and Mexico.
2. Countries in which production is irregular in normal times but in which potential reserves are considerable, and production becomes important at high-price levels: The former Austrian Empire, Bolivia, Australia (Victoria), Burma, South Africa, Italy, Spain, and Asia Minor.
3. Countries in which normal production is small and in which known reserves are probably less important: United States and Alaska, Canada, Peru, Germany, Turkey (Asia Minor), Serbia, Portugal, Borneo, Indo-China, and Japan.
[Plate VI] shows the geographical distribution of the chief antimony deposits of the world.
The production statistics of the various countries are so little in accord that it is impossible to give more than a rough comparison between the important producers. As nearly as can be estimated the output of antimony ore in 1913, the last year for which even approximately complete statistics are available, amounted to about 20,000 metric tons of recoverable antimony. The consumption is even more difficult to estimate, as customs figures for different countries vary widely. The following table shows the relative importance of the principal producing and consuming countries in terms of percentage of the world’s output in 1913: