INTRODUCTION
N
EARLY all the known
varieties of precious stones are found in the United States, but there
is very little sysÂtematic exploration for them, as the indications
seldom justify the investment of much capital in such search. The daily
yield from the coal and iron mines, or from the South African diamond
mines, or a week's yield of the granite quarries, would exceed in value
the entire output of precious stones found in the United States during
a year. Systematic search for gems and precious stones has been carried
on in only two States— Maine and North Carolina. Otherwise, the gems
are found accidentally, in connection with other substances that are
being mined, or in small veins which are only occasionally met with, as
the turquoise in Mexico. They are often gathered on the surface, as is
the case with garnet or olivine from Arizona and New Mexico ; or in
sluicing for gold, as the sapphires from Montana ; or in connection
with mica mining, as the beryl from Connecticut and North Carolina ; or
from the beds of streams and decomposing rocks, as the moss-agate from
Wyoming ; or on the beaches, as the agate, chlorastrolite, and
thomsonite from the shores of Lake Superior.
Nearly
all the gems found in these various ways are sent to the large cities
in small parcels, or sold in the neighborhood to tourists, or sent to
other places to be disposed of as having been found in their vicinity.
Many of them are only known locally, some to mineralogists, while
others, mentioned in the following
