MARCELINE. 

 the time. Although less in request than 

 formerly, large quantities of this stone are 

 cut and polished in Geneva and the French 

 Jura, and exported thence all over the 

 world. It takes a good polish, and is 

 cut in facets like rose-diamonds. In this 

 state it possesses all the brightness of the 

 polished steel, -whicli is now so ftishionable, 

 without its tendency to become oxidised by 

 exposure to the atmosphere. The Marcasite 

 of commerce (which includes Pyrites pro- 

 per) is generally small, rareh^ Attaining the 

 size of a stone of two carats. The stone 

 whicli the ancient Peruvians polished and 

 used for min-ors was a variety of Marcasite 

 which occurred in large plates, none of which 

 are found now. See Pierre des Incas. 



Marceline, Beudant. An impure variety 

 of Braunite. S.G. 4*75. 

 Analysis, by Damour : 

 Peroxide of manganese" . 67'37 

 Protoxide of manganese . 19*17 

 Peroxide of iron . . . 1*45 



Silica 7-71 



Lime 1-22 



Gangue .... 272 



99-o4 



Locality. St. Marcel in Piedmont. 



Brit. Mus., Case 13. 



Marekanite. a variety of Pearlstone 

 occurring in the form of pearly-white 

 grains composed of thin concentric layers. 



Locality. Marekan, in the Gulf of Kamts- 

 chatka. 



Brit. Mus., Case 30. 



Margarite, Fuchs, Phillips. Ehombic ; 

 hemihedral, with an oblique aspect. Basal 

 cleavage perfect. Occurs in thin crj'stal- 

 line laminae, which intersect each other in 

 all directions, and have the lateral planes 

 striated horizontally. Colour pale pearl- 

 grey, passing into reddish- and yello.wish- 

 white. Translucent. Lustre pearly on the 

 terminal planes, vitreous on the others. 

 Streak white. Laminae rather brittle. In 

 thin leaves slightly elastic. H. 3-5 to4'5. 

 S.G. 2-99. 



Comp. R5 si + 3A12 Si + 3H - silica 30-] , 

 alumina 51*2, lime 11*6, soda 2-6, water 4*5 

 = 100. 



Analysis, by Smith ^ Brush : 



Silica . 



. . 28-47 



Alumina 



. 50-24 



Peroxide of iron . 



. 1-65 



Lime . 



. 11-50 



Magnesia . 



. 0-70 



Soda, with a trace of 



potash 1-87 



MARIATITE. 229 



Water .... 5-00 



99-26 



55 intumesces and fuses. 



Is attacked by acids. 



Localities. — Sterzing in the Tyrol, in 

 foliated Chlorite. Greinerberg, Zillerthal, 

 with Chlorite. With Corundum at Kathe- 

 rinenberg in the Ural. The emery localities 

 in Asia Minor and the Grecian Archipelago. 

 Pennsylvania, North Carolina, &c., U.S. 



Name. — From Margarita, a pearl; be- 

 cause of its peculiar pearly lustre. 



Brit. IMus., Case 32. 



Margarodite, Dufrenoy, Schaffhdutl. 

 A hydrated Mica ; rarely occurring in fine- 

 grained laminae, in which case it bears a 

 great resemblance to Mica. Colour dull 

 green, passing into bright green. Lustre 

 sometimes opalescent, sometimes like mo- 

 ther-of-pearl. Slightly translucent at the 

 edges. Easily pulverised. H. 2-5. S.G. 2-87. 



Comp. R Si + 2it Si + 2H, or I2(ll3 Si2) 



+ 3(Mg, Si2) + F-'e S> + 6Na si + 9K si- 

 Analysis, from Pfitsch, by Hlasiwitz ; 



Silica 



Alumina 



Peroxide of iron . 



Potash . 



Soda . 



Lime . ... 



Loss by ignition . 



45-50 

 33-80 

 6-25 

 7-31 

 6-22 

 0-48 

 0-36 



99-90 



BB in fine lamina? fuses, emitting a vivid 

 light and j-ielding a white enamel. With 

 borax yields a colourless glass. 



Notafi'ected by acids. 



Localities. The S.E. of Ireland, in gra- 

 nite. The Zillerthal, forming the matrix of 

 black Tourmaline. St. Etienne in 'France, 

 in graphic granite. Poorhouse Quarry, 

 Chester co., Pennsylvania, U.S. ; Munroe, 

 associated with Topaz and Fluor. 



Margode. a bluish-grey stone resem- 

 bling clay in external appearance, but so hard 

 as to cut spars and zeolites. (^Nicholson). 



Marialite, Ryllo. See HAiivNE. 



Mariatite. a variety of Blende, in 

 which part of the zinc is i-eplaced by iron 

 and sometimes by cadmium. Occurs in 

 tetrahedrons and massive. 



Comp. 3Zn, S + Fe, S. 



Analysis, by Boussingault ; 



Sulphide of zinc . . . 76'8 

 Sulphide of iron . . . 23-2 



100-0 



q3 



