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856
MINERAL RESOURCES.
Amatrice is especially adapted for jewelry where matrix stones are desired. It has bright colors of its own, and does not resemble the green seen in discolored turquoise matrix. The variety of com­binations of matrix and colors is probably greater than that found in turquoise, and the rich green of amatrice is more attractive in cer­tain classes of jewelry than the blue of turquoise. The gems are generally cut in rounded or cabochon forms and are used in rings, scarf pins, brooches, necklaces, pendants, etc. Amatrice is becom­ing popular and the Occidental Gem Corporation reports a produc­tion of about 45,000 carats during 1908. The gems are retailed at $1 to $3 a carat.
Utahlite.—The utahlite or chlorutahlite mine is in Clay Canyon, 1-1/2 miles west of Fairfield, Utah County, at the south end of the Oquirrh Mountains. It is operated intermittently whenever a new supply of gem material is needed. The deposit is located at the foot of the hill on the north side of the canyon, a few feet above the bottom. The walls of the canyon, or more properly valley, are not steep at this point. Development consists of a tunnel 110 feet long, driven nearly north into the hill, and an open cut with a small incline. The tunnel did not cut the variscite lead. The country rock exposed in the workings is black limestone, which strikes about N. 50° W., with a dip of 22° N. The variscite lead has a steeper dip to the north, nearly 45°, with approximately the same strike as the limestone. The variscite occurs in concretionary nodules in a brecciated, more or less decomposed, zone. Practically everything in this zone has a nodular shape, including the blocks of limestone breccia, etc. Chert forms a prominent part of the filling of the mineralized zone and has been fractured and cemented by calcite seams and limonite stains. The nodules of variscite range from one-fourth of an inch to over 4 inches in thickness. The nodules have been more or less fractured, and the cracks have been filled in with yellow and white phosphate minerals. Some of the larger nodules contain two or more smaller nodules or irregular masses of variscite, inclosed in yellow and white matrix or shells. Most of the nodules are surrounded by banded layers of the yellow phosphate and some have white coatings also. The colors of the variscite range from deep grass or emerald green to paler shades and nearly white. The deeper colors show a tendency to appear near the borders of the nodules. Some of the variscite nodules yield large pure gems of beautiful color. Others furnish handsome matrix stones, though the number of variations of pattern and the contrasts of colors occur­ring in small areas are not so great as in amatrice. Some of the yellow phosphate mineral, with or without thewhite in seams through the massive variscite, furnishes exceedingly attractive gems.
The nodular and brecciated chalcedony and phosphate minerals associated with variscite at both the amatrice and utahlite mines would furnish handsome material for small ornaments of mosaic work, even where there is no green variscite present. The concre­tionary and agate-like structure of the nodules and the massive matrix with small nodules throughout give odd patterns and effects. Where the colors are marked, as in much of the yellow phosphate mineral and chalcedony the matrix could even be used for gem purposes.