Ch. 2: Precious Gem stones in 1908

Ch. 2: Precious Gem stones in 1908 Page of 82 Ch. 2: Precious Gem stones in 1908 Text size:minus plus Restore normal size   Mail page  Print this page
850
MINERAL RESOURCES.
of turquoise than that now found. It is therefore thought probable that the same material will be found again.
The Aztec Turquoise Company ships for cutting only the best
{ pure blue turquoise and high-grade matrix. Large quantities of low-grade, soft, and offcolor rough and matrix material is thrown away or buried. The gems are cut at the company's shop in New York and the pure stones are guaranteed. They are marked on the back with an AZT monogram occupying the space of one letter. The best turquoise comes from the Monte Cristo claim. It has a rich deep blue color and takes a brilliant polish. The matrix stones show pleasing contrasts between the dark blue of the turquoise and the dark-brown limonite stains, with sometimes gray quartz or rock fragments.
The portion of the William Tell claim worked by the Arizona Turquoise Company is directly below and adjoins on the south the Monte Cristo claim of the Aztec Turquoise Company. The deposit is on the steep, cliff-like northeast slope of Ithaca Peak, down which the waste rock from the workings slide several hundred feet. The operations consist of a cut in the mountain side with a working face nearly 50 feet high. This face is carried back by steps or benches 12 to 15 feet high. Deep holes are drilled and the rock of the suc­cessive benches pushed out on to the floor of the cut by blasts. In this way masses weighing several hundred tons are loosened and broken so that they can be sledged and the turquoise picked out. Where patches of fine blue turquoise occur they are carefully chipped out with gads and chisels. The turquoise is closely sorted, only the better grades being shipped. The greenish, pale blue, and soft turquoise is discarded and destroyed. Some very fine pure blue turquoise of deep color is obtained, though the principal yield is in matrix gem material. Guy Atlee, superintendent, states that occa­sionally lumps of over a pound in weight of nearly pure turquoise are obtained. The lumps are generally of matrix and come from enlarged portions of the turquoise seams. The latter occur plenti­fully in parts though without definite position through the rock. In the workings no attempt is made to follow particular seams through any distance, but the rock is quarried as a whole, and the turquoise seams and patches are picked out of the blocks. The method of the occurrence of the turquoise in decomposed, silicified quartz porphyry is the same as in the Aztec Company's mine directly above. The gem material is all shipped and cut at the company's plants in New York and Denver.
' The deposit of turquoise worked by the Los Angeles Gem Company, a few hundred feet northwest of that of the Arizona Turquoise Com­pany, is also located on the very steep northeast slope of Ithaca Peak, above a rocky cliff. The mining, which is under the supervision of E. E. Peck, president of the company, is open-cut work. Large masses of rock are broken down by blasting, and the turquoise is removed by carefully breaking the blocks. The turquoise occurs in seams cutting decomposed, silicified quartz porplvyry in various directions. The principal yield is in matrix turquoise, though some pure turquoise also is obtained. The gems are shipped to Los Angeles where they are cut in the company's shop. An odd stone was recently cut by this firm showing a blue letter Y of turquoise in a gray matrix. This stone was sent to a student at Yale University. The cutting so
Ch. 2: Precious Gem stones in 1908 Page of 82 Ch. 2: Precious Gem stones in 1908
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US Geol. Surv. 1908. Gemstones, Metals.
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