2

gion. Baron von Foullon' separates the porphyrites of the Tyrol into quartz-porphyrites, quartz-mica-porphyrites, and diabaseporphyrites. In connection with the first group, Von Foullon records the replacement of hornblende by augite near the contact of the quartz-porphyrite and granite. The second group is characterized by the presence of garnet and an epidote, with the unusual pleochroism wine-yellow and violet. Intergrowths of this mineral and hornblende take place in such a manner that the axes ɓ and c' of the former are parallel with c' and б of the latter. The hornblende in the rock often shows a parting parallel to op. In the Neues Jahrbuch Cathrein describes six rocks from various localities in the Alps. A staurolite-mica-schist occurs at Oberinnthal. It contains numerous hemimorphic crystals of tourmaline. A garnet amphibolite is remarkable for the occurrence in it of plagioclase pseudomorphs of garnet. The interior of the garnets are changed into plagioclase, around which is an exterior zone of compact hornblende. The serpentine of this region is an altered pyroxene rock. The remains of bronzite, enstatite, and diallage can still be detected in it. The most instructive portion of the paper is that devoted to the porphyrites and pitchstone-porphyries. Of the former several varieties are recognized. The first contains epidotized plagioclase and crystals of compact hornblende. In the second, in which uralite and a little augite occur instead of hornblende, the plagioclase is sausuritized. A third variety contains brown garnets in oscillatory combinations of the dodecahedron and the icositetrahedron. They are the oldest constituent. Of the pitchstone-porphyry the author says, this rock occurs in large independent masses, breaking through the prevailing quartz-porphyry in large dikes and bosses, no transition between the two being anywhere discernible.-A schistose rock from the Grossarlthal in the Alps contains chloritoid instead of mica as its bisilicate constituent. Cathrein 3 calls it a chloritoid schist. It contains nearly five per cent. of rutile and sphene. The rocks of the Hereroland in Southwest Africa belong principally to the class of the older eruptives. The quartz grains of some of the granites contain fluid inclusions with hexahedral crystals, and are pierced through by little needles of sillimanite. The most interesting observations are those on the crystalline schists. The gneiss is remarkable for the unusual association and decomposition of its constituents. The biotite is intergrown with sillimanite, and contains zircon crystals surrounded by pleochroic "höfe." Orthoclase and microcline are intergrown in the manner described by Becke.5 The former has

I

Jahrb. d. k. k. geol. Reichsaust, 1886, p. 747.

2 Neues Jahrb. f. Min., etc., 1887, i. p. 147.

3 Min. u. Petrog. Mitth., viii., 1887, p. 331.

4 H. Wulf, Min. u. Petrog. Mitth., viii., 1887, p. 193.

5 Cf. Min. u. Petrog. Mitth., iv., Taf. ii. Fig. 8.

undergone alteration into pseudophite, yielding a product having very much the appearance of serpentinized olivine. The augite gneisses are divided into scapolite-bearing varieties and those that contain wallastonite. The cleavage in the scapolite, as observed by Wulf, is parallel to ∞P, and is not parallel to ∞P∞, as given in the text-books. The latter is probably a parting. The composition of the augite in both varieties approaches that of diopside. Other rocks described by Wulfare diorites, basalts, amphibolites, diorite-schists, mica-schists, etc.-Lacroix describes a gabbro from St. Clement in the Puy-de-Dôme, which contains, in addition to the usual constituents, the minerals vesuvianite, sphene, and wallastonite. The feldspar is anorthite with only 0.53 per cent. of Na2O. It presents the appearance of having been crushed and recemented, the cementing material possessing the same optical orientation as the pieces it surrounds.

Mineralogical News.-Within the past few months the properties of quite a number of rare minerals have been investigated by mineralogists in this country and in Europe, with the results indicated below. W. C. Brögger' describes in detail the characteristics of låvenite and cappelinite. The former occurs on the island Låven in Langesundsfjord, and is also found in the eleolite syenite of the Province of Rio Janeiro, Brazil. It forms brown to yellow, slightly transparent crystals, with a prismatic habit and vitreous lustre. It is monoclinic in crystallization with à: 5 : c' = 1.0811: 1:0.8133, P=71° 24%. The twinning and the cleavage planes are parallel to the orthopinacoid, while the plane of the optical axes is the clinopinacoid. The mineral is strongly pleochroic, ĉ>b> a=red-brown, yellowish-green, and wine-yellow. Its specific gravity is 3.51, and its composition:

Sio2 ZrO2 Fe2O, (?) MnO CaO Na,O Loss at red heat

5.64

5.06

I 1.00 11.32

1.03

33.71 31.65 Cappelinite is found in a small vein in the augite syenite of Little Arō in Langesundsfjord. It occurs in thick brown hexagonal prismatic crystals with a fatty lustre. Their axial ration is 10.4301. Their analysis yielded:

SiO2 B2O Y2O, La(Di),O, Сe2O, ThО, Bao Cao Na2O K2O H2O 14.16 17.13 52.55 2.97 1.23 0.79 8.15 0.61 0.39 0.21 1.81 Warwickite, the borotitanate of magnesium and iron, occurring at Edenville, N. Y., is generally found in prismatic crystals elongated in the direction of the vertical axis, with a cleavage parallel to the clinopinacoid. Lacroix3 has succeeded in obtaining measurements of these, which indicate a symmetry corresponding to that of the rhombic system. In accordance with

1 Zeitsch. f. Kryst., x., 1885, p. 503, and Geol. För. i. Stockh. Förh., Bd. vii. p. 598. Fr. Graeff, N. J. B., 1887, i. p. 201. 3 Bul. d. 1. Soc. Fr. du Min., ix. p. 74.

2

this view the plane of their optical axes is the orthopinacoid. Their bisectrix is positive and perpendicular to P‰. 2 E=125°. The mineral is pleochroic in red and brown tints. Withamite from the porphyrites of Glencoe, County Argyle, Scotland, the same author regards' simply as epidote. He also thinks that mismondine, sasonite, ottrelite, venasquite, and phyllite are merely varieties of chloritoid, the optical properties of which he describes at length. Xantholite he supposed to be identical with staurolite.-J. Strüver does not consider gastaldite as a variety of glaucophane, but regards both minerals as distinct members of the amphibole group. According to Lacroix 5 the kirwanite (of Thomson) is a mixture of amphibole, secondary quartz, and epidote. The same author finds that hullite from Belfast is not homogeneous, and therefore should not be regarded as a definite mineral species. He states also that Dufrenoy's dréelite is an impure barite.-New analyses of agalmatolite indicate that most of the substance to which this name has been given really possesses no definite composition, but is probably a mixture of silica and hydrated silicates of potassium and aluminium, resulting from the decomposition of orthoclase. An apparently regular mineral has been found by Vom Rath in the druses of an andesite near the apex of Cerro S. Cristobal near Pachuca, Mexico. It occurs in small octahedra, sometimes twinned according to the spinel law. It is often intergrown with tridymite. Hardness = 6-7. Specific gravity 2.27. Its composition is SiO, 91 per cent. Fe2O3.Al2O3 = 6.2 per cent. Both Vom Rath and Bauer regard it as most probably regularly crystallizing silica. It has been called christobalite to distinguish it from quartz, tridymite, vestan (Jensch, Pog. Ann., 1858, p. 320), and asmanite.A new variety of dufrenite has been observed by Messrs. Kinch, Butler,9 and Miers in Cornwall, England. When fresh it is found in small black or apple-green orthorhombic plates, which in the thin section appear yellow or brown. Its hardness is 4.5 and specific gravity 3.233. An analysis yielded:

=

H2O 10.68

10

=

The composition of the mineral corresponds with that of Streng's kraurite. The composition of a micaceous mineral from a limestone in the Kaiserstuhl is recorded by Knop" as follows:

Sio, TiO2 A1,03 Fe,O, Mn,O,
35.91 1.15 15.18

10.85

Bul. d. 1. Soc. Fr. du Min., ix. p. 75.

2 Ib., p. 76.

0.89

4 Neues Jahrb. f. Min., etc., 1887, i. p. 217.

5 Bul. d. 1. Soc. Min. d. Fr., viii., 1885, p. 428.

MgO K2O H,O 22.80 2.90 10.77

3 Ib., p. 78.

6 Ib., p. 435.

7 Min. Mag., July, 1886, pp. 24 and 29; Dec. 1886, p. 74.

8 Neues Jahrb. f. Min., etc., 1887, i. p. 198.

9 Min. Mag., Dec. 1886, p. 65.

10 Neues Jahrb. f. Min., 1881, i. p. 101.

"Zeits. f. Kryst., xii. p. 607.

This mineral differs from biotite in the possession of water and a smaller percentage of potassium. As Hoppe-Seyler' found that when biotite is subjected to the action of carbon dioxide and water it loses potassium and gains water, Knop thinks that this mineral, which he calls pseudobiotite, may have been formed in the same way, especially as it is found most abundantly near the contact of limestone with phonolite. Knop further discusses the constitution of biotite, but reaches no conclusions further than that the atomic relations of its constituents are SiO, R2O: Ro=2: 1: 1.5, corresponding to the formula R."R""SiO3Professor A. H. Chester3 has recently communicated some notes on the chemical composition of a few obscure American minerals. Fuchsite from Aird Island, in Lake Huron, occurs in small layers and masses in a crystallized dolomite. According to Professor Chester's analysis it contains:

Sio, Al2O3 Cr2O Fe,O, CaO MgO K,0 Na2O H2O 45.49 31.08 3.09 trace 0.51 3.36 9.76 0.90 5.85 A pink celestite from Landsville, Oneida County, N. Y., yielded results corresponding to a mixture of 84 per cent. SrSo, 11 per cent. BaSo, and 5 per cent. CaSo. The mineral has been called baryto-celestite, but Professor Chester considers it more probably an isomorphous mixture of the three carbonates. In addıtion to the analyses given above, there are in the paper quite a number of new analyses reported, the most interesting being those of okenite, scorodite, brochantite, and zinkenite.-Igelström reports the existence of a manganiferous vesuvianite with 4.72 per cent. of MnO.

6

Crystallographic News.-Chas. O. Trechman 5 describes crystals of barite from Addiewell in Midlothian, England. They are found in small brilliant crystals covering rhombohedra of pearl spar and the dull faces of an older genera of barite. The new forms detected upon them are 7P, 38P, P. 4P, P, and P, ǎ: b: c' = .8152 : 1 : 1.3136.—The examination by Hussak of fluorite crystals from various localities, with reference to the question of optical anomalies, has revealed nothing definite in regard to the anomalous action in this case. He finds, however, that the structure of the mineral corresponds to the orthorhombic symmetry, with the axis of least elasticity normal to one of the cubic faces.-Mr. H. A. Miers? mentions orthoclase twins from the augite andesite of Kilimanjaro, in which the composition face (as well as the twinning plane) is the orthopinacoid. The crystals are bounded by the planes P, 2P∞, ∞ Pão, and op.

Zeits. d. deuts. Geol. Ges., 1875, p. 515. 2 Zeits. f. Kryst., xii. p. 588.

4 Bul. d. 1. Soc. Fr. d. Min., ix. p. 22. • Zeits. f. Kryst., xii. p. 552.

3 Amer. Jour. Sci., April, 1887, p. 284. 5 Min. Mag., Dec. 1886, p. 49.

7 Min. Mag., July, 1886, p. 10.

Miscellaneous.-Fremy' has succeeded in obtaining small well-colored crystals of ruby by subjecting to a red heat a mixture of alumina and minium, and also by heating to a high temperature equal weights of alumina and barium fluoride. In both cases the color was produced by the addition of small quantities of potassium bi-chromate. Measurable crystals of quartz have been produced by heating an enclosed dialysed solution of silica to a temperature of 320°. The crystals, 1⁄2 mm. in length, possessed the forms R, -R, ∞R, and in two cases + Tridymite was obtained by fusing pieces of very acid rocks with the powder of basalts and melaphyres.A concretion of coarse tourmaline pegmatite in the tourmaline granite near Pisek, Bohemia, contains pseudomorphs3 of pyrite after tourmaline. The rare mineral langite has been found by Von Foullon forming the cement of a breccia in Pockwerke, Garnstein.

2P2

4.

Comptes Rendus, civ., 1887, p. 737.

2 Chrustchoff, Neues Jahrb. f. Min., etc., 1887, i. p. 205. 3 E. Döll, Verh. k. k. geol. Reichs., 14, p. 350.

Sept. 24, 1887.

4 Ib., 1886, p. 464