210 LASURSTEIN. 



Lasurstein, Werner. See Lapis Lazuli. 

 Latialite, Ha'dy. A name given to 

 Hailyne, after Latmm (one of its localities), 

 in the neighbourhood of Rome. 



Latrobite, Brooke, Gmelin. A variety of 

 Anorthite, occurring in crystalline masses, 

 and in oblique rhombic prisms. Colour pale 

 rose-red. Lustre vitreous. Opaque. Cleav- 

 age in three directions. Fracture uneven. 

 H. 5 to 6. S.G. 2-72 to. 2-8. 



Analysis (mean of two), by C. Gmelin : 



Silica 43-21 



Alumina .... 34-82 

 Peroxide of iron . . . 3-16 



Lime 9-03 



Potash 6-57 



Magnesia . . . .0-62 

 Water ..... 2-04 



99-45 



BB in the platinum forceps fuses with 

 intumescence to a white enamel ; with borax 

 yields a globule which is pale amethyst-red 

 in the outer flame, and colourless in the 

 inner one. 



Locality/. Amitok Island, on the coast of 

 Labrador, with Felspar, Mica, and Calc Spar. 



Name. After the Rev. C. J. Latrobe, by 

 whom it was first brought to this country. 



Brit. Mus., Case 3L 



Laumonite, PhilUps, Nicol; Laumon- 

 TITE, Haiiy ; Lomonit, Werner; Lomonite, 

 Jameson. Oblique : primary form an oblique 

 rhombic prism. Occurs in aggregated co- 

 lumnar or radiating crystalline masses, or in 

 separate crystals, related in form to Augite. 

 Colour white or yellowish-white, sometimes 

 with a slight tendency to reddish. Lustre 

 vitreous, pearly on the cleavage plane. 

 Transparent or translucent. Becomes opaque 

 and pulverulent on exposure to the atmo- 

 sphere. (See Efflorescent Zeolite.) 

 Streak white. Very brittle. H. 3-0 to 3-5. 

 b.G. 2-29 to 2-36. 



Fig. 2.53. 



Camp. Ca3 «i2 + 3Al Si2 + 12 H = silica 

 5M, alumina 21-8, lime 11'9, water 15-2 

 = 100. 



Analysis, from Huelgoet, by Malaguti §• 

 Durocher. S.G. 2-29: 



Silica ..... 52-47 

 Alumina . . . • « 22-56 



LAZULITE. 



Lime 9-41 



Water 15-56 



100-00 



BB intumesces and fuses to a frothy mass ; 

 with borax forms a colourless glass. 



Forms a jelly with nitric or muriatic acid. 



Found in greenstone and in cavities of 

 amygdaloid. 



Localities. — Scotch. Hartfield Moss, Ren- 

 frewshire, /^r. 252, in translucent white crvs- 

 tals. Loch Screden, Isle of Mull, /^, 253. 

 Long Craig, Dumbarton Muir; near Old 

 Kilpatrick, Dumbartonshire. Carbeth, Stir- 

 lingshire. Glen Farg, Fifeshire, of a deep 

 red colour.— Irish. The Mourne Mountains, 

 in granite. Ballintoy, with Stilbite. — 

 Foreign. In trap in Iceland, the Faroe 

 Islands, Disko in Greenland. St. Gotthard, 

 in Switzerland. Eule, in Bohemia, in clay-^ 

 slate. Fassa-Thal, in the Tyrol, in large 

 masses with a radiated sti-ucture. Nova 

 Scotia, at Peter's Point, Port George, and 

 coloured green by copper at Margaretville. 



Name. After Gillet de Laumont, engi- 

 neer and mineralogist, by whom it was 

 discovered in 1785, at the lead mines of 

 Huelgoet, in Lower Brittany. 



Brit. Mus., Case 28. 



Lave Vitreuse du Cantal, Beudant. 

 See Cantalite. 



Lavendulan, Breithaupt. Amorphous : 

 occurs in thin reniform crusts, which are 

 the result of the alteration of other ores. 

 Colour lavender- blue. Lustre greasy, in- 

 clining to vitreous. Translucent. Streak 

 paler than the colour. Fracture conchoidal. 

 H. 2-5 to 3. S.G. 3-014. 



Comp. Arsenous acid, the oxides of cop- 

 per and cobalt, lime, sulphuric acid, and 

 water. 



BB fuses easily, colouring the flame of a 

 deep blue, and affording a globule which 

 becomes crystalline when cool. 



Locality. Annaberg, in Saxony, with ores 

 of cobalt, nickel, and copper. 



Lavezzo. See Potstone. 



Lazionite. See Lasionite. 



Lazulite, Haiiy, La Metherie; Lazur- 

 stein, Werner. See Lapis Lazuli. 



Lazulite, Dana; Lazulith, Werner. 

 Oblique: primary form a right rhombic 

 prism. Generally occurs granular or mas- 

 sive. Colour various shades of azure-blue, 

 inclining to green or white. Lustre vitreous. 

 Slightly translucent. Streak white. Brittle. 

 Fracture uneven. H.5to6. S.G. 3 to 3-122. 



