The
comparison for. different years indicates that agate and chalcedony
are the only gems that show a marked increase. Californite, beryl,
chrysoprase, rose quartz, tourmaline, turquoise, and variscite show
decrease in production, the remaining gems, sapphire, feldspars,
garnets, spodumene, opal, peridot, topaz, rhodonite, and others of less
importance show an irregular and varying output from year to year.
PRODUCTION.
The
total production of gems and precious stones in the United States in
1915, as reported to the Geological Survey, was valued at $170,431. The
production for 1914 was $124,651, the lowest since 1898, and that for
1915 is the second lowest.
Value of precious stones produced in the United Slates, 1911-1915.
