LEPOLITE. 

 Analysis, by Soltmann : 



Silica ..... 37-40 

 Alumina .... 11-60 

 Peroxide of iron . . . 27-66 

 Protoxide of iron. . .12-43 

 Lime, Magnesia . . . 0-26 



Potash 9-20 



Water 0-60 



99-15 

 BB acquires a pinchbeck-brown colour, 

 and fuses to a black magnetic globule ; with 

 borax forms a bottle-green glass. 



Eeadilj'- soluble in muriatic acid, with 

 separation of silica in the form of the crystal- 

 line scales of the mineral. 



Localities. — Irish. Three Rock Moun- 

 tains, CO. Dublin, in granite. — Foreign. 

 Petersberg, Wermland, in Sweden. 



Name. From Aesj-/?, a scale, and f^'-^^o^s, black, 

 Lepolite. a variety of Amphodelite 

 from Lojo and Orrijerfvi in Sweden. The 

 crystals are sometimes two inches long. 

 Analysis, from Lojo, by John Hermann: 



Silica 42-80 



Alumina .... ob'l2 

 Peroxide of iron . . .1-50 



Lime 14-94 



Magnesia .... 2-27 

 Potash .... 1-50 



Loss by ignition . . .1-56 



99-69 

 Lettsomite, J. Percy. Occurs in spheri- 

 cal globules, or in druses composed of short 

 delicate fibres of a smalt-blue colour, with a 

 velvet-like appearance. Lustre pearly. 



leucite. 



215 



(Cu6 S + 3H) + (A1 S + 9H)- 

 sulphuric acid 16*78, oxide of copper 49-85, 

 alumina 10-76, water 22-75 = 100. 

 Analysis, by Dr. John Percy ; 



Sulphuric acid . . . 14-12 

 Alumina . . . .11-06 

 Peroxide of iron . . . 1-18 

 Oxide of copper . . . 46-59 



Water 23-06 



Insoluble . . . .2-35 



98-36 



Locality. Sparingly at Moldawa in the 

 Bannat, coating cavities in earthy hydrous 

 oxide of iron. 



Name. After W. G. Lettsom, Charge 

 d'affaires and Consul-General to Uruguay, 

 and one of the authors of " The Mineralogy 

 of Great Britain and Ireland." 



Brit. Mus., Case 55. 



Leucachates. The name given by 

 the ancients to white varieties of Agate. 



From xivxosi white, and'A;tocT»i,-, Agate (which 

 see). 



Leucanterite. The name proposed by 

 Professor C. U. Shepard for an efflorescence 

 on the Copperasine found at Ducktown Cop- 

 per Mine in Eastern Tennessee. 



Leuchtenbergite, Komonen. A variety 

 of Chlorite occuring crystallized in regular 

 six-sided pyramids. Colour yellowish, 

 internally greenish. Very translucent; 

 transparent in thin laminae. Soft like Gyp- 

 sura. S G. 2-71. 



Analysis, by Hermann 





Silica 



. 32-35 



Alumina 



. 18-00 



Peroxide of iron . 



. 4-37 



Magnesia 



. 32-29 



Water . . . 



. 12-50 



99-51 



Locality. Slatoust in the Ural. 



Brit. Mus., Case 32. 



Leucite, Werner. Cubical : usual form 

 the trapezohedron,/5r. 258 : often occurs dis- 

 seminated in grains. Colour yellowish or 

 greyish-white, passing into ash-grey, or 

 smoke- grey ; rarely reddish-white. Lustre 

 vitreous. Translucent: opaque when de- 

 composed. Streak white. Brittle. Fracture 

 imperfect-conchoidal. H. 5-5 to 6. S.G. 

 2-483 to 2-49. 



Fig. 258. 



Comp. Anhydrous Analcime. K^ ^i^ + 



3A1 Si2 (Dana), orK Si + Al si^ = silica 55-i, 



alumina 23-4, potash 21-5=^100. 



Analysis, from eruption of Vesuvius of 



1845, by Rainmelsberg : 



Sihca 56-05 



Alumina .... 23-16 



Soda 0-30 



Potash 20-04 



Loss by ignition . , .0-52 



100-07 



Small quantities of lime and iron are also 

 frequently present. 



BB alone infusible : with borax or car- 

 bonate of lime melts Avith diificulty to a 

 clear glass. 



In a finely divided state, completely de- 

 composed by muriatic acid, with separation 

 of pulverulent silica. 



p 4 



