MINERALOGY. 471 



The luitlior regards this as correspoiidiii.i;' to a manganese silicate (Mn?, 

 SIOt) and antiuionate of iron (Fe3Sb208) in about the ratio of 4:1. 

 Langbanite is found at Langban, Sweden, in granuhir limestone with 

 schefferite, magnetite, and rhodonite. (Described by G. Flink, in the 

 Zeitschrift f. Kryst., 1887, vol. xxiri, }). 1.) 



Lansfonlite. — A white translucent mineral having a crystalline struct- 

 ure and vitreous luster. The hardness is 2.0, the specific gravity 1.54 

 to 1.09. An analysis by Keeley gave : 



CO2 MgO H2O 



18.90 23.18 57.79 = <)9.87. 



Of the very large amount of wafer contained 2G.3 per cent. were lost over 

 sulphuric acid at the end of a week. The formula deduced is SMgCOs, 

 Mg(Uri)2+21H20. It occurs as a stalactitic growth in the anthracite 

 coal mineof Lansford, near Tamaqua, Schuylkill County, Pennsylvania. 

 (Described by F. A. Genth in Zeitschr. f. Kryst, vol. xiv, p. 255.) 



Lauhanifc. — A new zeolitic mineral resembling stilbite from the 

 basalt, near Lauban, Silesia. It occurs in fine fibrous radiated snow- 

 white aggregates, sometimes spherical in form. The hardness is 4.5 

 to 5; the specific gravity 2.23. Au analysis gave: 



SiOi AI2O3 FeO CaO MgO HjO 



47.84 16.74 0.56 16.17 1.35 17.08 = 99.76. 



This corresponds to 2CaSiO.^, Al2(Si02):j, 6H2O, which brings it near 

 to laumontite. (Described by H. Traube in Jahrb. Min., 1887, vol. 

 ir, 64.) 



Lnurionitc. — A mineral of comparatively recent origin, having been 

 formed as the result of the action of sea-water upon the ancient lead 

 slags at Laurion, Greece, where there were lead and zinc mines worked 

 by the Greeks before the (3hristian era. Laurionite occurs in white 

 prismatic crystals related to mendipite in form, and has a hardness of 

 3.5. An analysis by Bodewig gave: 



PI) O Cl H^O 



79. 38 3. 17 13. 77 3. Gfi — 100. 



This gives the formula Pb(0n)2, PbCl2. 



Associated with the laurionite is another mineral in tabular mono- 

 clinic crystals and having the same qualitative composition. It is in- 

 ferred to be also an oxy-chloride of lead and has been named Fiedlcrife 

 after Baron Fiedler. (Described by G. vom Rath in Sitzungsber. Nied. 

 Ges. Bonn., June 0, 1887.) 



Mangano-tantaUtc. — A member of the tantalite-columbite group of 

 minerals from the gold washings in the Ural. It has the form and 

 habit of common columbite, but the specific gravity is 7.37, and the 

 color, though nearly black, is orange-red in thin splinters. The follow- 

 ing analysis by Blomstrand shows it to be pure taiitalate of manganese : 



igii. 



[0.17] = 100. .33, 



