Geology and Mineralogy. 91 



tem. Its hardness is 5-5-6, specific gravity, 3*85-3 -9, and refrac- 

 tive index higli, greater than l-'ZS. Only qualitative tests have 

 thus far been made, but it is hoped that material for a complete 

 analysis may be obtained. — Bull. Oeol. Univ. California, v, p. 

 331. 



Plancheite is a hydrated copper silicate described by La- 

 croix from Mindouli, French Congo. It occurs in fibrous masses 

 of a blue color associated with dioptase ; specific gravity, 3'36. 

 An analysis by Pisani gave : 



SiO^ 37-16 CuO 59-20 FeO tr. H,0 4-50 = 100-86. 



Named after M. Planche.— ^?<^/. Soc. Min., xxxi, 250, 1908. 



RisoRiTE is a niobate of the yttrium and cerium metals with 

 other elements ; it is described by O. Hauser from the pegmatite 

 of Risor in southern Norway. It has a brown color, and is opti- 

 cally isotropic, probably from alteration ; hardness, 5-5 ; specific 

 gravity, 4-179; after ignition, 4-678. It is not far from fergu- 

 sonite, but contains uranium in very small amount only. — Ref. 

 in Jahrb. Min., i, 37, 1910. 



RosAsiTE is a carbonate of copper and zinc, described by D. 

 Lovisato from the Rosas naine, Sulcis, Sardinia. It occurs in 

 mammillary masses with fibrous structure and green to sky-blue 

 color ; hardness, 4-5, specific gravity, 4-07. Analysis gave : 



CO2 CuO ZnO PbO H5O 



30-44 36-34 33-57 tr. 0-21 = 100-56 



— Rend. Ace. Line., xvii (2), 723, 1908. 



Vashegtite is a basic aluminium phosphate described by 

 Zimanyi, from the iron mines of Vashegy, Hungary. It occurs 

 in dense white masses resembling meerschaum and immediately 

 associated with variscite ; hardness, 2-6. An analysis by Loczka 

 gave : 



P2O5 AI2O3 FejOa H2O K2O NasO CO2 insol. 

 31-32 28-33 1-19 3897 0-16 0-05*0-12 0-24=100-38 



The calculated formula is \N\^!>^.2,Yf)^.'&()B.fi.—Zeitschr. Kryst., 

 xlvii, 53, 1909. 



Samsonite is a sulphantimonite of silver and manganese from 

 the Samson vein of the St. Andreasberg silver mines in the Harz ; 

 it is described by Werner and Fraatz. It occurs in monoclinic 

 crystals, the color is red by transmitted light and it somewhat 

 resembles miargyrite. An analysis, after deducting unessential 

 constituents, gave : 



S 20-45 Sb 26-33 Ag 45-95 Mn 5-86=98-59 



This leads to the formula 2Ag,S.MnS.Sb,S3.— Centralblatt Min., 

 p. 331, 1910. 



12. Zics Cristallisations des Grottes de Helgique ; par W. Prinz. 

 Pp. 90, with 143 figures. Brussels, 1908. — The stalactitic forma- 

 tions in limestone caverns have often been described, but never 



