These crystals are extraordinary objects to the eye of the mineralogist; to see flat spodumenes of characteristic form as large as a man's hand, but with bright luster and perfect transparency and of this rich delicate pink-lilac tint is a novel and unlocked for experience.
These elegant tourmalines and spodumenes occur near the top of a ridge lying from a mile to a mile and a half from the lepidolite ledge of the old Pala locality, and separted from it by a valley some 900 feet deep. The ledge in which these new minerals occur is on the west side of this ridge and has been traced for 1,200 feet in a northwestsoutheast direction. The description given of it suggests a large dike. The rock is a coarse decomposed granite (pegmatite), the feldspar much kaolinized and reduced to a red dirt, and with many large quartz crystals, some of them reaching 150 pounds in weight, but not clear. This remarkable occurrence was first announced by the writer, in Science for August 28, 1003," and in the American Journal of Science for September, 1903,* and was further discussed by Dr. Charles Baskerville, in Science for September 4, 1903.''
The locality was visited in the summer of the same real" by Mr. Waldcmar T. Schaller, then of the department of geology of the University of California, now of the United States Geological .Surrey, and a remarkable account of it was published by him in September. He described the occurence as follows:''
The formation in which these fine crystals are found at the Pala locality consists of a pegmatite dike, dipping westerly at a low angle, perhaps 20 degrees. It is more or less broken, and as a whole seems to form the surface of much of the slope of the hill on which it occurs. The dike is rather broad, but irregular * * * and has a thickness of not more than 30 feet.
Mr. Schaller goes on to say that the remarkable presence of lithia minerals is not found throughout the dike, but is apparently confined to certain rather small portions. This is a curious fact in lithology, and not readily explicable. The rock is mainly a coarse granitic aggregate of quartz and orthoclase, with some muscovite and rather broken and rounded crystals of black tourmaline. At times, however, lepidolite comes in, replacing the muscovite, and with it appear the colored tourmalines instead of the black; and associated with these are the spodumenes. The tourmalines and the lepidolite are frequently inclosed in the quartz and feldspar (as notably also at the Mesa Grande tourmaline locality, and at Haddam Neck, Conn.), but the spodumenes are rarely so found. They usually occur free, in pockets, like the hiddenito spodumene of North Carolina; and from this fact Mr. Schaller at that time regarded them as of later formation.
"Science, new ser., vol. 18, Xo. 452, 1903, p. 280. b Am. Jour. Sci., 4th ser., vol. 16, 1903, pp. 264-267. ''Science, new ser., vol. 18, 1903, pp. 303-304.
rt Schaller, Waldeniar T-, Spodumene from San Diego County, Oil.: Hull. !>rpt. (ieol. I'niv. California, vol. :;, September, 1903, pp. 265-275.
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