Elements of mineralogy, crystallography and blowpipe analysis from a practical standpoint .. . numerous. Transparent crystals are found in Minas Geraes, or FIBROLITE. Composition.—Al(AlO) SiO^. General Description,—Long, almost fibrous orthorhombic crystals, and fibrousor columnar masses of brown or gray color. Physical Characters.—Transparent to translucent. Lustre, vitreous. Color,brown, gray, greenish. Streak, white. H., 0 to 7. Sp. gr., to , parallel to brachy pinacoid. 378 DESCRIPTIVE MINERALOGY. Before Blowpipe, Etc.—Infusible, becomes dark blu
Elements of mineralogy, crystallography and blowpipe analysis from a practical standpoint .. . numerous. Transparent crystals are found in Minas Geraes, or FIBROLITE. Composition.—Al(AlO) SiO^. General Description,—Long, almost fibrous orthorhombic crystals, and fibrousor columnar masses of brown or gray color. Physical Characters.—Transparent to translucent. Lustre, vitreous. Color,brown, gray, greenish. Streak, white. H., 0 to 7. Sp. gr., to , parallel to brachy pinacoid. 378 DESCRIPTIVE MINERALOGY. Before Blowpipe, Etc.—Infusible, becomes dark blue with cobalt solution. In-soluble in acids. Remarks.—Chiefly found in mica schist, gneiss, etc. Sometimes with andalusite. Uses.—In the stone age it was used for tools, weapons, etc., being second only tojade in toughness. DATOLITE. Composition.—Ca()SiOt. General Description.—Highly modified, glassy, monocliniccrystals. Usually colorless, but also white or greenish. Also incompact, dull, white or pink masses, resembling unglazed porcelain. Fig. 635. Fig. 636. Fig. Bergen Hill, N. J. -V^ Lake Superior. Crystallization.—Monoclinic. /? = 89° 51. Axes a:l: c = : I : Prominent forms are the pinacoids a and c,the unit prism m, negative unit pyramid /, unit clinodome d, clinoprism / = 2« : ^ : 00 c, and positive hemi pyramid r = a : b : ^ angles are mm = 115° 13 ; //= 103 31 ; pp = 120°55; ^^=76° 37- Physical Characters. H., 5 to Sp. gr., to 3. Lustre, vitreous. Translucent to nearly opaque. Streak, white. Tenacity, brittle. Color, colorless, white, greenish. Before Blowpipe, Etc.—In forceps or on charcoal fuses easilyto a colorless glass, and if mixed with a flux of acid potassiumsulphate and calcium fluoride and a little water it will color flamegreen. In closed tube yields water at a high heat. Soluble inhydrochloric acid, with gelatinization. Similar Species.—Differs from the zeolites in crystalline formand flam
Size: 2912px × 858px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyorkdvannostran
