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GEMS AND PRECIOUS STONES.                              329
Lepidolite in finely granular masses, pale-green albite, and small green tourmalines are abundant near many of the pockets. Muscovite surrounded by a border of lepido­lite, or in parallel growth with lepidolite, is also of common occurrence near the pockets. As in most of the gem-bearing pegmatites the tourmalines are seldom in their original positions on the walls of the cavities, but lie embedded in a sandlike mass of quartz fragments, cookeite, and other decomposition products at the bottom of the pockets. They are mainly grass-green to olive-green in color, becoming nearly colorless toward the tip. The exact apex of some of the crystals is pink and many of them show very perfect terminations. Gem tourmalines are not so abundant that it would pay to work the mine for these alone.
Most of the gems found in the feldspar mining were marketed irregularly through local collectors.
The associated minerals and tourmaline from Haddam Neck have been described by H. L. Bowman,1 as pinkish muscovite, lepidolite, greenish-white muscovite, tourmaline, apatite, microcline, albite, beryl, quartz, cookeite, fluorspar, microlite, and columbite. The tourmaline occurs in beautiful, transparent, striated, curved trian­gular prismatic crystals of various colors, the most common being light and dark green and pink. A few crystals are almost perfectly colorless. Color variations in the crystals are generally in transverse bands, either with sharp contacts or hazy gradations. In some crys­tals the color shades are delimited by planes corresponding to crystal terminations, yielding ghost or phantom crystals. Kunz states that crystals showing marked internal striations have been found which yield gems showing cat's-eye effects when cut cabochon across the prism. This property has also been found highly developed in some of the tourmalines from Mesa Grande, Cal.
The feldspar quarry of F. E. Strickland is about 2\ miles northeast of Portland, in the west side of Collins Hill. It is operated by Mr. Strickland under lease to the Eureka Mining & Operating Co., of Trenton, N. J., all of the spar, quartz, and mica going to the company and gems and other minerals being retained by Mr. Strickland. The quarry consists of two joining open cuts with north and south elonga­tion, parallel, and connected at the north end. The east cut is about 300 feet long, 65 feet wide, and 10 to 40 feet deep. The west cut is about 200 feet long, 50 feet wide, and 25 feet deep. A crosscut leads out to the hillside at the north end of the west cut.
The country rock is muscovite-biotite schist containing much black tourmaline near the pegmatite. The schist has a general north strike and a dip of about 20° W. It has been warped, however, to correspond approximately with the contact of the pegmatite. The pegmatite is a large irregular semibedded deposit both parallel with and cutting the schist in different parts. In the east deposit the outcrop was an elongated dome pitching under the schist at each end. That this body of pegmatite joins the one forming the west deposit under the surface is shown where the two open cuts join at the north end.
The pegmatite is coarse-grained containing large bodies of graphic granite, potash feldspar crystals 2 or 3 feet across, irregular quartz segregations several feet thick, and bunches or streaks of mica crystals. Cavities or pockets with crystal-lined walls are found irregularly dis­tributed in parts of the quarry, especially in the east working. These pockets range from small size up to one reported to be 4 feet long by
i Mineralog. Mag. and Jour. Mineralog. Soc. Great Britain, vol. 13, pp. 97-121,1903. Reviewed by G. F. Kunz, U. S. Geol. Survey, Mineral Resources U. S., 1902, pp. 841-842,1904.