270 DESCRIPTIONS OP MINERALS. 



elaion, oil. Altered crystals are in part the mineral Gie- 

 seckite. 



Diff. Distinguished from scapolite and feldspar by the 

 greasy lustre when massive, and its forming a jelly with 

 acids ; from apatite by the last character, and also its hard- 

 ness. 



Obs. Nephelite is the prominent constituent of nephelin- 

 doleryte or nephelinyte, and phonolyte, and occurs also in 

 some other eruptive rocks ; and it also enters into the con- 

 stitution of miascyte, zircon-syenyte, metamorphic rocks. 

 Among the localities are Vesuvius and C. di Bove, in Italy ; 

 Katzenbuckel, near Heidelberg ; Aussig in Bohemia ; and 

 as elaeolite, Brevig, Norway ; in Siberia ; in the Ozark 

 Mountains, Arkansas ; in Litchfield, Maine. 



Gancrinite. Crystals like those of nephelite, and compo- 

 sition similar, except the presence of some carbonates and 

 usually water. Color white, gray, yellow, green, blue, or 

 reddish; H. =5-6. GL =£^4-2*5. (5n account of the car- 

 bonates it effervesces in acids. B.B. fuses very easily. 



Occurs in crystalline rocks at Miask in the Ural ; in Nor- 

 way ; Transylvania ; and at Litchfield in Maine, with elaeo- 

 lite and sodalite. Supposed to be altered nephelite. 



Microsommite is near. Sommite (nephelite). 



Sodalite. 



Isometric. In dodecahedrons ; cleavage dodecahedral. 

 Color brown, gray, or blue. H. =6. Gr. =2-25-2 -3. 



Composition. Xa., Al O s Si 2 + j Na Cl= Silica 37*1, alumina 

 31-7, soda 19-2, sodium 4*7, chlorine 7-3 = 100. B.B. fuses 

 with intumescence to a colorless glass. Decomposed by hy- 

 drochloric acid, and the solution gelatinizes on evaporation. 



Occurs in eruptive and metamorphic rocks. Found in Si- 

 cily ; near Lake Laach ; at Miask ; in Norway ; West Green- 

 land ; of a blue color at Litchfield, Me. ; and lavender-blue 

 at Salem, Mass. 



Hauynite (or Hauyne'i and Xosite Cor Xosean) are related minerals 

 from lavas or other eruptive rocks ; and Ittnerite is altered hauynite 

 or nosite. Isometric. In dodecahedrons. Color bright blue, occasion- 

 ally greenish. Transparent to translucent. H.— 6. G. =2 4-2 5. 



Lapis-Lazuli. — Ultramarine. 

 Isometric. In dodecahedrons; cleavage imperfect. Usual- 

 ly massive. Color rich Berlin or azure'blue. Lustre vitre- 

 ous. Translucent to opaque. H. = 5 -5. GL =2 -3-2 -5. 



