from various sources, the latest being an article just published by Mr. G. A. Waring, of Leland Stanford University."
It is worth while to note the fact that there is already more actual mining for gems done in California than in any other State or Territory of the Union, and the indications are that there will be many more gem mines discovered in the southern counties as remote districts are opened and old ones more fully explored.
An extensive report, to appear as a volume, on the gems and jewelers' materials of California is now in press; this was prepared by the writer at the request of the State Mining Bureau, under the direction of the State mineralogist, Mr. L. E. Aubury. A report on the occurrence of lithia minerals in the United States, by Mr. Waldemar T. Schaller, of the United States Geological Survey, is also in preparation. As the lithia minerals are so intimately connected with the gem minerals, the latter will of necessity be more or less treated of in this report. These two publications will describe quite fully the remarkable mineralogical discoveries in southern California and make them known to the world. Heretofore almost all that has appeared, until very recently, has been in the annual reports of this Bureau by the writer. The privilege of using in this present summary the data obtained for the forthcoming volume has been very liberally accorded the writer by the California State Mining Bureau. A large amount of this material has been obtained from personal communications and other unpublished sources, and is now brought together and corrected to date, so as to furnish a general view of the gem resources of the State.
The distribution of gem minerals in California as a whole maj' be broadlj- outlined as follows: (1) There is first the gold region of the central and northern counties along the western base of the Sierra Nevada; in this are found the gold quartz used so much for jewelry and ornamental work, and the few but interesting diamonds. These latter occur loose in the gold-bearing gravels, sometimes of the surface placers but generally of the old river beds now covered and compacted by lava flows. In these old river beds also is found much of the agatized and opalized wood, which is sometimes capable of use as an ornamental stone. In the same gravel filling of an ancient stream bed in Calaveras Count}T was encountered the wonderful deposit of transparent quartz crystals (rock crystal) of great size, which 3'ielded some of the finest material for art work ever known anywhere.* These occurrences, it is true, are adventitious, and not in the nature of mines that can yield an}- permanent supply. But they have been found, and may be found again at any time. The gold quartz is different in this respect, and a fairly steady production of it in certain of the quartz mines may be relied upon hereafter as before.
a Waring, G. A., The Pegmatite Veins of Pala: Amer. Geologist, vol. 35. No. (i. June. 1905, pp. 356-369. bMineral Resources U. S. for 1898, Ann. Kept. U. S. Geol. Survey. 1899.