List of Plates (At End of Book)
PAGE Tourmaline crystals, growing amid feldspar crystals in a cavity in granite, from Paris, Me. 279 Plate 1.—Basal forms of the isometric system 311 Plate 2.—Basal forms of the tetragonal system. Basal forms of the orthorhombic system 312 Plate 3.—Basal forms of the monoclinic system. A cross section of the prism with its edges beveled so that a six-sided prism is formed (pseudo-hexagonal). Basal form of the triclinic system. 313 Plate 4.—Basal forms of the hexagonal system 314 Plate 5.—Gold in quartz from California (in color) 280 Plate 6.—Native silver in calcite. Argentite, the black masses throughout the white quartz (in color) 281 Plate 7.—Pyrargyrite as it appears after moderate exposure to the light; streak at left. Crystal form of pyrargyrite. Prousite as it appears after moderate exposure to the light; streak at left (in color) 282 Plate 8.—Native copper from Michigan. Chalcopyrite in tetrahedrons and an occasional octahedron; streak to the left (in color) 283 Plate 9.—Chalcocite crystals with the bluish tarnish. Tetrahedrite crystals; streak to left (in color) 284 Plate 10.—Tetrahedrons showing characteristic manner in which tetrahedrite occurs. A cube with the edges beveled and the corners cut in a form characteristic of cuprite 315 Plate 11.—Cuprite, the red crystals showing characteristic color, others showing the green tarnish of malachite. Malachite (green) and azurite (blue), the two minerals shown together as they very commonly occur (in color) 285 Plate 12.—Limonite. The crystal form in which goethite is found (in color) 286 Plate 13.—Hematite. Clinton iron ore, oolitic. Siderite crystals (in color) 287 Plate 14.—Crystal forms of hematite. A typical crystal of magnetite. The rhombohedron typical of siderite 317 Plate 15.—Pyrite crystals. Marcasite in concretionary form with radiate structure (in color) 288 Plate 16.—The pyritohedron. The pyritohedron with certain of its edges beveled by the cube faces, to show the relationship of these two forms 318 Plate 17.—Galena in crystals. Pyromorphite crystals (Green) (in color) 289 Plate 18.—Typical forms for cerrusite. Forms in which anglesite occurs 319 Plate 19.—Sphalerite, some the normal yellow and some crystals with the reddish tinge. (White is dolomite.) Zincite, streak to the left (in color) 290 Plate 20.—A characteristic form in which sphalerite may occur. Characteristic form for zincite crystals. Typical form of crystal of willemite 320 Plate 21.—Smithsonite in yellow crystals. Franklinite in octahedral crystals, streak to left (in color) 291 Plate 22.—Moss agates, showing the dendritic growth of manganitic minerals, like manganite or pyrolusite. Crystal form of manganite 321 Plate 23.—Crystals of green corundum in syenite, from Montana. Typical crystal forms of corundum 322 Plate 24.—Arsenopyrite, showing crystals massed so as to be incompletely developed. Realgar as it usually occurs in powdery incrustations (in color) 292 Plate 25.—Large crystals of stibnite; the light colored face is the one parallel to which cleavage occurs. Niccolite is a vein in slate (in color) 293 Plate 26.—Cobaltite, silver color, with pink tinge. Smaltite, pink is cobalt bloom (in color) 294 Plate 27.—Carnotite from Southwest Colorado. Cinnabar (in color) 295 Plate 28.—Cassiterite, twinned crystals. The crystal form in which both cassiterite and rutile occur when in simple crystals. Multiple twinning characteristic of rutile 323 Plate 29.—Crystal of spinel. Crystal forms in which dolomite occurs 324 Plate 30.—Two intergrowing or twinned quartz crystals. Diagram of the typical quartz crystal. A quartz crystal on which the left hand rhombohedron is represented by small faces, while the right hand rhombohedron has large faces 316 Plate 31.—Amethyst, not however deep enough colored for gems. Jasper, with botryoidal surface (in color) 296 Plate 32.—Banded agate from Brazil (in color) 297 Plate 33.—Common opal from Arizona. Siliceous sinter or geyserite from Yellowstone Park (in color) 298 Plate 34.—Orthoclase, a cleavage piece. Crystal forms of orthoclase. Diagram of a multiple twin of a plagioclase feldspar 325 Plate 35.—A group of microcline crystals from Pike’s Peak, Colo. Labradorite, showing multiple twinning (the striation) and the iridescent play of colors (in color) 299 Plate 36.—Crystal form of a pyroxene. Cross sections of a pyroxene crystal showing the lines of intersection of two cleavage planes. Cross sections of pyroxenes, showing typical forms taken by crystals. Augite crystals, in crystalline limestone (in color) 300 Plate 37.—Diagrams of amphibole crystals. Tremolite in silky fibrous crystals, asbestos. Hornblende crystals in quartzite 326 Plate 38.—The dodecahedron and the 24-sided figure characteristic of garnets. The garnet, grossularite. The garnet, alamandite (in color) 301 Plate 39.—Beryl of gem quality. Zircon in syenite (in color) 302 Plate 40.—Cyanite crystals in schist. A crystal of mica, showing basal cleavage (in color) 303 Plate 41.—Crystal form typical of topaz. A topaz crystal from Brazil. Crystal form typical of staurolite when simple. A typical twin of staurolite (in color) 304 Plate 42.—Epidote crystals. Typical forms of epidote crystals. Typical forms of tourmaline 327 Plate 43.—Serpentine. Chlorite (in color) 305 Plate 44.—The typical form of analcite. A typical natrolite crystal. The typical crystal form of stilbite. A sheaf-like bundle of fibrous crystals, typical of stilbite 329 Plate 45.—A group of calcite crystals. Typical forms of calcite 330 Plate 46.—Typical forms of aragonite. Typical form of the anhydrite crystal 331 Plate 47.—A piece of gypsum looking on the surface of the perfect cleavage, and showing the two other cleavages as lines, intersecting at 66°. Twinning is also shown. A simple crystal of gypsum. Twin crystals of gypsum. 332 Plate 48.—A group of barite crystals. Outline of the typical tabular barite crystal. The six-sided double pyramid, composed of three interpenetrating crystals, typical of witherite and strontianite 328 Plate 49.—Apatite crystals in crystalline calcite. The ends of apatite crystals showing common modes of termination (in color) 306 Plate 50.—A group of fluorite crystals. A group of halite crystals (in color) 307 Plate 51.—Sulphur crystals. Ice crystals, the top one, the end of a hexagonal prism; the two lower figures multiple twins as in snow flakes 333 Plate 52.—The Devil’s Tower, Wyoming, an example of igneous rock with columnar structure, and resting on sedimentary rocks 334 Courtesy of the U. S. Geological Survey Plate 53.—A coarse granite. Graphic granite 335 Plate 54.—Syenite. Gabbro 336 Plate 55.—Basalt-porphyry. The large white crystals are phenocrysts of plagioclase feldspar. Basalt-obsidian 337 Plate 56.—Amgydoloid 338 Plate 57.—The north face of Scott’s Bluff, Neb., showing sedimentary sandstones above and clays below. The type of erosion is characteristic of arid regions 339 Courtesy of the U. S. Geological Survey Plate 58.—Breccia. Conglomerate 340 Plate 59.—Calcareous shale. Coquina 341 Plate 60.—Foramenifera from chalk; enlarged about 25 diameters. Encrinal limestone; fragments of the stems, arms and body of crinoids 342 Plate 61.—Amber. Two bottles of petroleum, the left hand one with a paraffin base, the right hand one with an asphalt base (in color) 308 Plate 62.—Diatomaceous earth magnified 50 times. Two diatoms from the above enlarged 250 times 343 After Gravelle, by the courtesy of Natural History Plate 63.—A metamorphic rock, showing the contortion of layers due to expansion under heat 344 Plate 64.—A conglomerate partly metamorphosed to a gneiss. A typical gneiss 345 Plate 65.—Mica schist, with garnets. Chlorite schist (in color) 309 Plate 66.—Phyllite. A white marble, with black streaks due to graphite 346 Plate 67.—Serpentine composed of serpentite, hematite, and some calcite (in color) 310 Plate 68.—Claystones, simple and compound. A lime concretion, which on splitting disclosed a fern leaf of the age of the coal measures 347 Plate 69.—A septeria from Seneca Lake, N. Y. Pisolite from Nevada 348 Plate 70.—A geode filled with quartz crystals 349 Plate 71.—A quartz pebble from the bed of a New England brook. A pebble of schist and granite from the foot of Mt. Toby, Mass. 350 Plate 72.—An iron-nickel meteorite, of 23 lbs., which fell in Claiborne Co., Tenn. An etched slice of an iron meteorite which fell in Reed City, Osceola, Co., Mich. 351 Plate 73.—A stone meteor, about natural size, which fell in 1875 in Iowa Co., Iowa 352