1870.] Mineralogy. 127 



meteoric stone which fell near Frankfort, in Franklin Co., Alabama, 

 on the 5th December, 1868.* 



Attention has again been called to the occurrence of pseudo- 

 morphs in Bunter sandstone after scalenohedra of calcite.t The 

 discoveries of Dr. Blum, already noticed in this Journal, have been 

 supplemented by those of Dr. Klocke, from which it appears that 

 the pseudomorphs occur in several new localities in the neighbour- 

 hood of Heidelberg. 



A new mica, related to biotite and phlogopite, has been described 

 by Yon Kobell under the name of Aspidolite, in allusion to the 

 basal face of the crystals often resembling an oval shield (aairl^). 

 The crystals are small rhombic prisms, of a dark olive-green colour, 

 and are found in the chlorite of the Zillerthal in Tyrol. { 



So complex is the chemical constitution of that curious mineral, 

 the Tourmaline, that Mr. Kuskin not unaptly calls it " more like 

 a mediaeval doctor's prescription than the making of a respectable 

 mineral." In spite of its complexity, Eammelsberg has lately 

 succeeded in reducing all his analyses of this substance to the 

 general' type of the silicate K 6 Si 5 , where K is considered 

 monatomic, and may represent six atoms of any of the monads 

 hydrogen, potassium, sodium, and lithium ; or three atoms of the 

 dyads magnesium, calcium, manganese, and oxygen ; or two atoms 

 of the triads boron and aluminium. § All tourmalines fall into two 

 sections — one represented by the general formula K 3 Al 2 B Si 2 O i0 , 

 which is, of course, obtained by doubling the molecule above ; whilst 

 the second section contains nine of these molecules written thus : — 

 K 6 Al 12 B 4 Si 9 45 . 



Eammelsberg has also published a chemical note on the con- 

 stitution of Axinite, and on some native compounds of tantalium 

 and niobium. || 



Some good crystals of Gadolonite — the mineral in which yttria 

 was first discovered — have been examined by M. Des Cloiseaux.lF 

 He finds the crystals from Hitteroe to be doubly refracting, and to 

 contain from 10 to 12 per cent, of glucina; while those from 

 Ytterby are singly refracting, and contain no glucina. 



Dr. Sadebeck, of Berlin, whose examination of the crystalline 

 forms of copper-pyrites has already been referred to in this Journal, 

 has lately directed his studies to another common mineral zine- 

 blende, and has produced an elaborate paper on the hemihedral 

 forms of this cubic mineral.** 



* Silliman's ' American Journal of Science,' Sept., 1 869. 

 t Leonhard und Bronn's ' Jakrbuch,' No. 6, 1869, p. 714. 

 % ' Sitzungsberichte d. K. bay. Acad. d. Wissenschaften,' 1869. 

 § ' Monatsber. d. k. preuss. Ak. d. Wiss.,' 1869, p. 601. 

 || ' Zeitschrift d. deutsch. geol. Gesell.,' No. 3, 1869, pp. 555, 689. 

 f ' Annales de Chimie et de Physique,' Nov., 1869, p. 305. 

 ** ' Zeit. d. d. geol. Gesell.,' 1869, No. 3 7 p. 620. 



