. Economic Papers. ed. In those beds or portions of beds where there has been littlepegmatization monazite occurs sparingly. The same is true where pegmati-zation has been complete and but little of the original gneiss remains. Itis, then, the beds of gneissic rock which are rich in secondary quartz andcontain numerous small masses of feldspar throughout that carry the mostmonazite. In such rocks there is generally much biotite, with graphite andperhaps some muscovite and other accessory minerals, as well as abundantquartz and feldspar. The quartz occurs in layers or scattered grainsthroughout
. Economic Papers. ed. In those beds or portions of beds where there has been littlepegmatization monazite occurs sparingly. The same is true where pegmati-zation has been complete and but little of the original gneiss remains. Itis, then, the beds of gneissic rock which are rich in secondary quartz andcontain numerous small masses of feldspar throughout that carry the mostmonazite. In such rocks there is generally much biotite, with graphite andperhaps some muscovite and other accessory minerals, as well as abundantquartz and feldspar. The quartz occurs in layers or scattered grainsthroughout the rock, inclosing and replacing the other constituents. Thefeldspar crystals chiefly replace, though they partly displace, the otherminerals of the rock. Monazite in a rock matrix almost invariably possessescrystal form, in places having brilliant faces and sharp angles. As a typical example of rich monazite-bearing rock, that from the BritishMonazite Companys mine, 3 miles northeast of Shelby, is chosen for de-. Mostly quartz Mostly biotite, Feldspar Muscovite Monazite little quartzand graphite Figure 27.—Hand specimen of monazite-bearing rock from British Monazite Companys Mine,3 miles northeast of Shelby, N. C. Three-fourths natural size. scription. Fig. 27 represents a section across a hand specimen of this rockand shows the main feature to which attention will be called below. Thechief constituents of this rock are quartz, feldspar (mostly the potashvariety), biotite, graphite, muscovite, monazite, and a little zircon. It hasa banded structure caused by the more or less separate occurrences of cer-tain minerals arranged in parallel streaks, with a roughly parallel orienta-tion of the crystals or grains of each mineral. The principal features of thebanding as seen in the section consist of one large quartz streak with sev-eral smaller streaks and individual grains in a regular biotite schist. Theother minerals of the section occupy various positions and show diverse re
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