Small amounts of high-quality amber mica have been shipped from Ceylon to England.
Deposits of excellent quality mica are known to exist in the McDonald range, in South Australia, from which small shipments have been made sporadically. This is the only district from which lepidolite or lithia mica has been noted in sheets of commercial size.
In China, large deposits of muscovite mica are reported from the vicinity of Kiao-Chau bay and also from Shantung, but no commercial development has taken place, and it is believed that the deposits are worthless as a source of sheet mica.
Prior to 1914 efforts to produce mica in Norway on a commercial scale met with no success and little is known of the deposits. The great need of mica in Germany during the war stimulated production in Norway, tremendous prices being paid for the material.
CHANGES IN KNOWN GEOGRAPHICAL DISTRIBUTION IN THE NEAR FUTURE
The most important change in known geographic distribution of mica for the near future concerns the increased development of the South American fields. During the war Brazilian mica found considerable favor both in this country and Europe, and the better grades are considered equal to the best India mica. Importations of mica from Brazil were of much importance in meeting the large demands of the United States for mica of high quality to fill government needs. Owing to the nature of mica deposits in general, it is not safe to make estimates concerning reserves. This is particularly true of Brazil, where the industry is young, and careful prospecting and development have not been carried far. From the large number of known deposits and the rapidity with which the industry responded to war demands, despite difficulties in transportation from the mines to the seaboard, it would appear that Brazilian mica will play an increasingly important part in the mica markets of the world, particularly of the United States. No matter how great the merit of the mines of a district may be, however, unless the mica is carefully prepared, graded as to size and quality, and shipments are standardized, it cannot expect to attain permanent favor among consumers in this country or in Europe.
Less is known concerning the future possibilities of Argentina as a mica-producing country of importance. Many deposits are known and considerable shipments have been made to the United States and to Europe. The material received here has not been equal to Indian or Brazilian mica.
There is every reason to expect that India will retain its position as the most important mica-producing country. The great number of deposits offer almost every grade of muscovite required in the trade. The industry is well-established, and labor conditions are extremely favorable for the production of a commodity requiring such a large amount of hand labor before being ready for market. It is true, however, that the richest and most easily accessible deposits have been mined out, and scientific methods must be applied to mining if production is to retain its former place.
It is doubtful whether the immediate future will see any important change in the position of the United States as a mica producer. Although the reserves of the country as a whole are probably large, the deposits are small and the percentage of high-quality mica is not great. Production of important amounts of medium-grade mica will continue. Labor conditions are not favorable to producing cheaply an article that has a large part of its value determined by preparation and careful grading.
Scientific methods have been applied to the mining and preparation of a considerable part of the Canadian output. Reserves are large and Canada will undoubtedly retain for many years its position as the principal source of amber mica.