microscope, may on the other hand reach in veins in coarse-grained granites a length of a foot or more. As ornamental stones only certain varieties of Feldspar are valued and their value depends on accidents of color or structure. The first of the Feldspars which may be mentioned as being prized as an ornamental stone is amazonstone or green Feldspar. This in composition is what is called a potash Feldspar, potash being the alkali which in combination with alumina and silica goes to make up the mineral. The percentages of each in a pure amazonstone are silica 64.7, alumina 18.4 and potash 16.9. The mineralogical name of the species is micro-cline, meaning small inclination, and refers to the fact that the angle between the two cleavages of the mineral is not quite a right angle. The common color of microcline is white to pale yellow, but occasionally green and red occur. It is only to the green variety that the name of amazonstone is applied, a name meaning stone from the Amazon river. It first referred probably to jade or some such green stone from that locality and then came to include green Feldspar. No occurrence of green Feldspar in that region is now known. Practically all the amazonstone now used for ornamental purposes comes from three localities. These are the vicinity of Miask in the Ural Mountains, Pike’s Peak, Colorado, and Amelia Court House, Virginia. In all these places the amazonstone occurs in coarse-grained granite and is closely accompanied by quartz and Feldspar. All gradations are found in color from the deep green to white, only the bright green being prized for ornamental purposes. The Feldspar is usually well crystallized and crystals of several pounds weight may be found. A crystal will rarely be of a uniform color, streaks of paler green or white being commonly present. Only the uniformly colored portions are prized for ornamental purposes. The green often takes on a bluish tone and blue sometimes even predominates. The color is doubtless due to some organic matter, as it disappears, leaving the stone white, on heating. The stone is always opaque. Its use is not extensive, its sale being greater to tourists in the vicinity of the regions where it is found than to gem cutters. Several other localities in the United States besides those mentioned afford the mineral, though not in large quantities. It occurs in two or three localities in North Carolina; in Paris, Maine; Mount Desert, Maine; Rockport, Massachusetts; and Delaware county, Pennsylvania. The finest comes from the Pike’s Peak locality. Mr. G. F. Kunz states in regard to these crystals that when they were first exhibited at the Centennial Exposition in Philadelphia in 1876 they were a great surprise to Russian dealers who had brought over some amazonstone from the Urals, expecting to sell it at what would now be considered fabulously high prices. [Illustration: FELDSPAR. LOANED BY FOOTE MINERAL CO.]