as a Branch of Natural History^ ^c, 253 



metric water, which, in escaping, produces no change in the transparency of 

 the mineral. 



Family 1. — ^Gkmmoids. 



Insoluble and unalterable in acids ; fracture (cleavages excepted) conchoi- 

 dal, passing to uneven, and scaly. The hardest scratch quartz, the setter 

 only felspar. Specific gravity 2.5 to 4.2 



Gen — Quartz (with calcedony, amethyst, and ferrugineous quartz) ; zir- 

 con ; garnet (with almandine, grossular, cinnamonstone, aplome, melanite, 

 common and mixed garnets) ; staurotide or grenatite ; idocrase or vesuvian 

 (with egeran, loboite, and cyprine) ; Andalusite ; topaz ; tourmaline (with 

 rubellite, indicollite, and schorl) ; iolite or cordierite ; emerald (with beryl) ; 

 euclase ; peridot or chrysolite ; condrodite ; axinite. 



Appendiv. — Saphirin ; fibrolite ; Sommervillite ; Humite ; Forsterite ; hya- 

 losiderite; Sillimanite. 



Family 2. — Gadolinites. 



Soluble into a gelatinous mass in acids ; scratching quartz ; texture com- 

 pact or imperfectly foliated ; conchoidal fracture. Specific gravity 3.2 to 4.2. 

 Gen.— Gadoliiiite ; orthite. 



Family 3. — Hauynes. 



Soluble in a gelatinous mass in acids ; scratching apatite ; scratched by 

 quartz ; texture compact ; lustre between vitreous and greasy. Specific gra- 

 vity 2.2 to .3.6. 



Gen — Leucite or amphigene ; haUyne ; lazulite ; sodalite ; eudialite ; hel- 

 vine ; nepheline (with elaolite or Fettstein) ; mellilite ; gehlenite ; sphene ; 

 anorthite. 



Appendix.— litnerite I Indianite ; Berzeline ? (new mineral from LaRiccia, 

 near Rome.— JSi6/. Univ. Jan. 1831.) 



Family 4. — Labradorites. 



Soluble in a gelatinous mass in concentrated muriatic acid ; scratching apa- 

 tite ; texture foliated. 

 Gen — I^abrador felspar. 



Family 5. — Felspars. 

 Insoluble in acids. Specific gravity 2.3 to 2.5. Scratching apatite ; tex- 

 ture foliated ; primitive forms oblique prisms. 



Gen.— Albite or cleavelandite; felspar ; periklin ? petalite. 

 Appendix — Oligoklas (Breithaupt) ? 



Family 6. — Wernerites. 



Unalterable in acids. Specific gravity 2.6 to 2.8. Scratching apatite; 

 scratched by felspar ; compact or very imperfectly foliated texture. With the 

 blowpipe easily fusible, with intumescence. Primitive forms pyramidal. 



Gen. — Wemerite or scapolite ; meionite. 



Appendix.— DiYtyxe ; nutallite. 



Family 7- — Allanites. 

 Soluble in heated muriatic acid, with a silicious or gelatmous residue. 



