. Bulletin - New York State Museum. Science. 92 NEW YORK STATE MUSEUM tbene is found in norites and other granular eruptive rocks, a series of which may be found in the vicinity of Peekskill, West- chester co. N. Y. Pyroxene (augite) Pyroxene is essentially a normal metasilicate of calcium and magnesium, also containing iron, manganese or zinc and some- times small percentages of potassium and sodium. The many varieties are usually classified as nonaluminous and aluminous. ,^i--. xr Fig. 209 Pj'roxene Fig. 210 Pyroxene occurs in monoclinic crystals of prismatic habit with well developed termin
. Bulletin - New York State Museum. Science. 92 NEW YORK STATE MUSEUM tbene is found in norites and other granular eruptive rocks, a series of which may be found in the vicinity of Peekskill, West- chester co. N. Y. Pyroxene (augite) Pyroxene is essentially a normal metasilicate of calcium and magnesium, also containing iron, manganese or zinc and some- times small percentages of potassium and sodium. The many varieties are usually classified as nonaluminous and aluminous. ,^i--. xr Fig. 209 Pj'roxene Fig. 210 Pyroxene occurs in monoclinic crystals of prismatic habit with well developed terminations (fig. 208, 209); these crystals have a nearly square or octagonal cross section composed of the faces of the unit prism which has an angle of 93° (nearly 90°) and the faces of the ortho and clino pinacoid (fig. 210). A strongly marked parting parallel to the basal pinacoid is very character- istic, and is well shown in the specimen reproduced in The crystals are often thick and short. Massive forms are granular, foliated or columnar in structure but rarely fibrous. The luster is vitreous, resinous to dull and the color usually some shade of green, but also white, brown, or black. VARIETIES Diopsid or malacolite CaMg(Si03)2. Usually white or pale green in color. Hedenbergite (CaFe) (Si03)2. Color grayish green to black. Augite. An aluminous pyroxene chiefly CaMg(Si03)2 but con- taining aluminium and iron. Color dark green, brownish green to Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York State Museum; New York State Museum. Albany : New York State Education Dept
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