PHYSIOGRAPHY. 



Leucite Leucopyrite. 



LEPIDOKROKITE. (See Limonite.) 



LEPIDOLITE. (See Mica.) 

 LEUCITE. Trapezoidal Kouphone-Spar. MOHS. 



Primary form. Cube. 



Secondary form. Trapezohedron. Irregular forms and 

 grains. 



Cleavage, very imperfect parallel to the primary form, 

 and also to the faces of the rhombic dodecahedron. Frac- 

 ture conchoidal. Surface of crystals even, though gene- 

 rally rough ; of grains, uneven and smooth. 



Lustre vitreous. Color reddish, yellowish, or grey- 

 ish-white ; ash grey or smoke grey. Streak white. Semi- 

 transparent . . . translucent. 



Brittle. Hardness = 5*5 . . . 6-0. Sp. gr. = 2-483. 



Compound Varieties. Massive : composition granular ; 

 faces of composition irregularly streaked. Rare. 



1. Alone before the blow-pipe, U is infusible : with borax, or carbon- 

 ate of lime, it fuses with difficulty into a clear globule. Reduced to pow- 

 der, it is said to change the. color of the blue tincture of violets to green. 

 2. Analysis. 



By KLAPROTH. By ARFWEDSON. 



fr. Vesuvius. fr. Albano. fr. Albano. 



Silica . . 53-750 . 54-00 . 56-10 



Alumina . . 24-625 . 23-00 . 23-10 

 ^Potash . . 21-350 . 22-00 . 21-15 



Oxide of iron , 0000 . 0-00 . 0-90 



3. It occurs chiefly in imbedded crystals and grains in lava, sometimes 

 in compound specimens ejected by Mount Vesuvius. Besides this lo- 

 cality, it is also found at Albano and Frescati near Rome. 



LEUCOPYRITE. Axotomous Er uthleucone- 

 Pyrites. 



Primary form. Right rhombic prism. Mon M = 122 

 26'. 



