By George P. Kunz.
This paper is founded on and is a resume of the nine papers on the precious stones of the United States written since 1882 for the annual reports of the Division of Mining Statistics and Technology of the V. S. Geological Survey, on a report for the Eleventh United States Census, and the following is a condensation of these, together with additional information obtained from studying the collections in the United States and from personal examination of many of the localities where gems are found, and some notes on the gems and precious stones shown at the World's Columbian Exposition. The reader should also consult "Gems and Precious Stones of North America."(a)
Systematic mining for gems. Although nearly all the known varieties of precious stones are found in the United States, there has been very little systematic exploration for them until very recently, as the indications seldom justified the investment of much capital in such search. Whereas mining for precious stones was only carried on in two States in 1889, the following gems were mined in 1893: Tourmaline in Maine, emeralds in North Carolina, turquois in New Mexico, sapphires in Montana, and opal in Washington state, Idaho, and Oregon. Otherwise the gems are found accidentally in connection with other substances that are being mined. They are often gathered on the surface, as is the case with garnet and olivine in Arizona and New Mexico; or in sluicing for gold, as with 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 of the gems found in these various ways are sent to the large cities in small parcels or are sold in the neighborhood to tourists, or sent to other places to be disposed of as having been found where they are sold.
DIAMONDS.
The occurrence of diamonds in the United States is chiefly confined to two regions, geographically quite remote. The first is a belt of country lying along the eastern base of the southern Alleghenies, from Virginia to Georgia, while the other extends along the western base of the Sierra Nevada and Cascade ranges in northern California and
a New York: 1892. 8vo, 363 pp., 24 pi. Scientific Pub. Co.
