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CHAPTER VIII.
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CYANITE, EPIDOTE, TOURMALINE, CHRYSOLITE (PERIDOT), SERPENTINE, SMARAGDITE, LAZULITE, MALACHITE, AND PEARLS.
CYANITE.
This mineral (also spelled kyanite) is a subsilieate of alumina almost identical in composition with andalusite, and very closely related also to topaz. It is named from the Greek kuanos, blue, in allusion to its prevailing color, and was also called by old writers sappar, from a corruption of sapphire, which the fine clear cyanites of deep tint sometimes resemble. It occurs generally in long prismatic or blade-like crystals, and is not uncommon in the gneissic rocks of New England and Southeastern Pennsylvania to North Carolina (Pls. XIII and XII, B). It presents various shades of blue and blue-green, occasionally varying to pure white, -—the variety from the Tyrol called rhcetizite. Fine crystals occur with lazulite at Clubb's and Crowder's mountains, on the road to Cooper's Gap, in Gaston County, and also in Rutherford County. Cyanite is somewhat frequently associated with corundum, from which Dr. Genth believed it to be derived by alteration. Another locality is at Swannanoa Gap, in Buncombe County; but the finest specimens are found in Mitchell County,1 where it occurs in distinct isolated crystals that, for perfection, depth of color, and transparency, rival those from St. Gothard. Switzerland. The locality is at an altitude of 5500 feet, near the summit of Yellow Mountain on the road to Marion, 4 miles southeast of Bakers-ville, in a vein of white massive quartz in a granitic bluff, associated with almandite garnet of a very light transparent pinkish-purple color. The vein has a dip of 60 degrees, bearing northeast and southwest. The color varies from almost colorless to deep azure-blue, as dark as the Ceylonese sapphire, also occasionally green. Some of the crystals are 2 inches long. while a few were observed 3/5 inch (15 millimeters) in width and 2/5 inch (10 millimeters) in thickness. Occurring in white quartz, they form beautiful specimens, and the loose crystals were extensively sold for sapphire some years ago, at Roan Mountain, the summer resort. A few
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