(EXTRACTED FROM THE AMERICAN NATURALISt, November, 1887.) MINERALOGY AND PETROGRAPHY.1 New Minerals.-Langbanite is the name applied by G. Flink' to a mineral which occurs in small black hexagonal crystals in a granular limestone at Långban, Sweden. In habit it is tabular or prismatic, with the prism faces but slightly developed. Its hardness is 6.5, specific gravity=4.918. Its axial ratio is I: 1.6437. Its analysis yielded, The discoverer regards it as silicate of manganese (Mn,SiO1) combined with antimonate of iron (Fe,Sb2Og) in the proportions 37: 10.-Webskyite.-This mineral, named by R. Brauns3 after the late Professor Websky, of Berlin, is a decomposition product of the serpentine occurring in the paleopikrite of Amelose, near Biedenkopf, in Nassau. It occurs in black amorphous masses, with a bluish-green streak. Its hardness is 3 and its specific gravity 1.771. It is apparently isotropic in thin sections, where it possesses a green color. Its composition is as follows: Sio, Al,O,. Fe,O, FeO MgO H2O Loss at 110° 9.60 3.13 13 21.20 This corresponds to the formula H ̧R,Si2O13+6H2O, in which R= Mg and Fe.-Laubanite is described by Traube as a new zeolite from the druses of the basalt occurring near Lauban, in Silesia. Its color is milk-white. It possesses a short columnar habit and a hardness of 4.5-5. It is found only in small crystals, implanted on phillipsite and other associated minerals. These crystals under the microscope are seen to be composed of little bundles of fibres. Its composition approaches very near to that of laumontite, from which it differs only in its percentages of calcium and water of crystallization. F. W. Clarke,5 of the U. S. Geological Survey, has recently published an interesting paper in which the relations between three American iron-micas are discussed. The three micas in question are lepidomelane from Baltimore, Md., and from Litchfield, Me., and annite from Rockport. Their compositions may be represented by the formulas RR"R" SiO (Rockport); R'R"R" SiO (Baltimore); and R'R"R"SiO 6 4 2 20 6 3 4 5 22 (Litchfield). Edited by DR. W. S. BAYLEY, Madison, Wisconsin. 2 Zeitschrift für Krystallographie, xiii., 1887, p. 1. 6 2 6 5 24 3 Neues Jahrb. f. Min., etc., Beil. Band., v., 1887, p. 318. The relations existing between them may be best shown by supposing two of the univalent groups (AIO) to replace one (RO). Assuming this, the formulas may be written: In the same paper there are also given analyses of iron-micas from Auburn, Me., and Pike's Peak, Colorado, and one of a muscovite from Alexander County, N. C., containing 1.10 per cent. of TiO2.Howlite.-This mineral was first identified by Professor H. How,' of Windsor, Nova Scotia, who named it silicoborocalcite. Messrs. Penfield and Sperry, having recently come into the possession of a comparatively pure specimen of the mineral, have re-examined it. They find it to be composed as follows: They regard it as a distinct species with the formula H,Ca,B,SIO14. -Cassiterite.-The tin-stone of Mexico is divided by Professor Genth 3 into two varieties, a red and a yellow variety. Both are supposed to have been formed by precipitation from solution. The red variety is found in very small crystals, with a hexagonal habit. Analysis shows it to consist of dioxide of tin, containing a little ferric oxide and occasionally small quantities of arsenic pentoxide. The yellow variety occurs principally in imitative forms. It contains very little ferric oxide, but considerable arsenic pentoxide, and always an admixture of zinc oxide. Crystals of cassiterite implanted on hematite (after the manner of rutile on hematite from St. Gothard), and pseudomorphs of the former after the latter mineral, as well as after magnetite, are described by Professor Genth as not very uncommon in the sands and ores from the state of Durango.-Mimetite has been found in small crystals at the Mina del Diablo, Durango, Mexico. More frequently, however, it occurs in pseudomorphic forms after an unknown mineral, supposed by Dr. Genth to be anglesite, by Professor von Rath to be galena, and by Dr. Brezina to be mendipite. Vanadinite.-This mineral occurs on quartz in the Mammoth Gold Mine, near Oracle, Pinal County, Arizona. It is sometimes coated with calcite, which is in turn coated with a second generation of vanadinite. Other localities for vanadinite are Yavapai County, Arizona; McGregor Mine, Grant County, New Mexico; and Bald Mountain Mine, Beaverhead County, Philos. Mag., iv. xxxv., p. 32. 2 Amer. Jour. Sci., Sept. 1887, p. 220. 3 Contributions from the Chemical Laboratory of the University of Pennsylvania, xxix., 1887, p. 4. 4 Ib., p. 10. Montana. Descloizite (ramirite), from San Luis Potosi, Mexico, yielded Professor Genth on analysis the figures,— a result not very different from that obtained by Penfield in 1883. Tapalpite, from the Sierra de Tapalpa, Jalisco, Mexico, is regarded by Rammelsberg as being represented by the formula Ag,S.Bi,Te. Professor Genth 3 has analyzed some comparatively pure material, with this result: which, after deducting the impurities, would give, as the composition of tapalpite, min corresponding to a normal sulpho-telluro salt of silver and bismuth. In the paper in which the above-mentioned minerals are discussed, Professor Genth describes pyrite pseudomorphs after pyrrhotite, from Colusa County, Cal.; hessite, from Tombstone, Arizona; allanite, from Statesville, N. C.; willemite, from Socorro County, New Mexico; and hisingerite pseudomorphs after calcite, from Ducktown, Tenn.-Bismutho-sphærite.—This eral has for some time been regarded as a basic carbonate of bismuth, but its composition has not until very recently been determined by means of analysis. A short time ago Mr. H. L. Wells obtained large specimens of the mineral from Willemantic and Portland, Conn. The Willemantic occurrence is described as a dark-gray mineral, holding in its centre a nucleus of bismuthinite. Its specific gravity is 7.42. Under the microscope it was seen to consist of a dark ground-mass, in which patches of a pale yellowish-green color are scattered. The dark portion is almost opaque from the numerous black dust-like inclusions it contains. These are supposed to represent traces of the original mineral from which the bismutho-spharite was derived. An analysis yielded,— corresponding to the formula BiO3.CO2 = (BIO),CO3—Crocidolite.-Messrs. Chester and Cairns have recently published an analysis of the bluish-gray fibrous crocidolite from Beacon Pole Hill, near Cumberland, Rhode Island, with the result (as the mean of two analyses): This composition is represented by the authors by the formula Fe,Na,H,Fe(Si,O3), = 3FeO.Na2O.2H2O. Fe2O3.9SiO2, in which the water is regarded as basic. The authors cannot accept the prevalent view that crocidolite is merely a fibrous arfvedsonite. -Datholite.-Mr. Whitfield' has analyzed the datholite from Bergen Hill, N. J., determining the boric acid by the Gooch method. His figures are: corresponding to the formula BO3. H2O. 2CaO.2SiO2 = H.CaSiO. BO2, the generally accepted formula for this mineral.-Ulexite.Ulexite, from Rhodes Marsh, Esmeralda County, Nevada, yielded the same analyst3 the following figures: SiO2 CI B2O3 SO3 0.04 2.38 43.20 0.28 CaO 14.52 Na,O 10. 20 K2O H2O 0.44 29.46 These figures are represented by the formula NaCaB,O, +6H2O, after making certain allowances for impurities. Siderite (sphærosiderite).—This mineral occurs at Baltimore, Md., associated with zeolites in the gneiss of the Jones Falls quarries. The crystals are small and lenticular in shape. They possess only the forms R and OR, except in one instance, where the negative scalenohedron -4R is supposed to occur. In these crystals the faces are generally rounded, forming a lens-shaped body. Frequently two of these lenses are grouped together so as to form apparent twins. And further, many lenses grouped together produce a perfect sphere. Analyses of selected material by Mr. A. G. Palmer gave, It is thought that the presence of manganese and zinc may have had some influence in the production of these rounded forms, not uncommon in the pure manganese carbonate-rhodochrosite. -Samarskite.-Samarskite 5 is found in the coarse-grained granitic veins cutting the schists in which the zeolites (referred to above) occur. It is described by Professor König as a very splintery, black mineral with a hardness of about 6-7. Its specific gravity is 6.146. An analysis yielded,— 3 L. c. Ib., October, 1887, p. 281. 2 Amer. Chem. Jour., ix., 1887, p. 23, and ii., 1880, p. 247. 4 Notes on the Minerals occurring in the Neighborhood of Baltimore, by G. H. Williams, Ph.D., Baltimore, 1887, p. 12. 5 Ib., p. 16. |