MINERALOGY. 



Al.i.orHiu>.TE, i.lan, Haily; fplmlcp garnet of Kar- 



ften. It is claffed with the garnet family by Werner, but 



i, regarded as a diftinft fpecies. It occurs maflive ; the frac- 



U,re"is uneven, paffing into concho.dal. Its colours are 



reenilh and yellowilb-grey : it is tranflucent on the edges ; 



-' ..,. °- r i.,rt„o It gives iparks 



It has hitherto 



i^lt^r^/khara giiiiening rellnous luftre. It gives Iparks 



Accord- 



vvith fteel. The fpecif.c gravity is^.5. . 



been f.mnd only in an iron-mine at Dramman, in Norway. 



It is lefs hard and lighter than common garnet. 



ing to Vauquclin, the conftituent parts are, 



Silex - - ' 



Aluminc 



Lime - - " 



Oxyd of iron 



Carbonate of lime 



Oxyd of manganefe 



100 



See Al- 



ALivfANDlNE, regarded as a variety of garnet 

 MANDIN ; but for granite r. garnet. , _, _ ,, 



Alum-Earth, Alum-Slate, Common and GloJJy, /ilum- 

 Stone. See Alum, Ores of. 



Aluminite, Subfulpbate of Aluminc; Reme thonerde, 

 Werner ; Alumtne pure, Haiiy. This mineral is of a fnov*'- 

 white colour, verging on yellowidi-white. It occurs in 

 reniform pieces, it has no luftre, the frafture is earthy, and 

 the confiftence between friable and folid. It is opaque. 



laft colour is very rare. In maflive varieties of amethyft, 

 feveral colours occur together. In cryftalHzation and other 

 properties, the amethyil does not differ from quartz. It 

 contains 97-50 of filex, with a minute trace of alumine, 

 oxyd of iron, and manganefe ; to thefe oxyds, no doubt, 

 its colours are owing. Amethylls occur in agate balls in 

 bafaltic rocks. Tliick fibrous amethyft occurs maflive and 

 in rolled pieces ; it occurs in agate veins, in the fame rocks 

 as common amethyft. A red colour is given to amethyfts 

 by the jewellers, by inclofing them in charcoal, which is 

 ignited, and allowed to confume gradually. When the colour 

 is not uniformly difFufed, it is expofed in a mixture of fand 

 and iron to a moderate heat, by which it is rendered more 

 uniform. 



Amianthus, Flexible ajbefius ; Am'iant, 'Vierner ; AJbeJie 

 amianthe, Fr. (See Amianthus, and Asbestus.) It is 

 found in ferpentine in the I fie of Anglefea, and in the fame 

 rock at Portfoy in Scotland. 



Ampelite is a bituminoui flate, or (hale, of which 

 drawing-flate, alum-date, and flate-clay, are varieties. See 

 Slate. 



Amphibole, hornblende. See Hornblende, Ad- 

 denda. 



Amphibole Lamellaire, common hornblende. 



Amphibole CryJlalH%ee, bafaltic hornblende. 



Amphibole AHinote. See Strahlstein. 



Amphibole Fibreux, glaffy adlinolite. See Stkahl- 

 stein. 



Amphibole Aciculaire, afbeftous a(f>inolite. See 



foils flightly, affords a gliftening ftreak, and adheres feebly Str^hlstein. 



to the tongue. It feels fine but meagre. The fpecihc gra- Amphibole Blanc et Scyeux, aftjeftous tremolite, gram- 



vityisl.66. A variety ofthe fame mineral lubllance occurs ^^^-^^ See Tremolite 



at Newhaven in Suffex, fiUing up filTures in chalk. This Amphibole Grammatite, common tremolite and glaffy 



1,-ariety ifc white, yields to the nail, and adheres Itrongly to ^^.g^oij^g * ' 



the tongue. The conftituent parts of tlie foreign aluminite Amphigene. See Leucite. 



32 

 47 

 19.25 



1.25 



Alumine . . - 



Water ... 



Sulphuric acid 



With a trace of filex, lime,l 

 and iron, equal iii fome > 

 fpecimens to - 3 



Amalgam, Native, femifluid and folid. 

 Ores of. 



Amanthoide, Capillary, and Amanthoidc, ByJfoUte ; the 

 latter fo called by Sauffure. The former appears to be a 

 variety of amianthus ; the latter refembles it, but differs 

 from it in chemical compofition, if the analyfisof Sauffure be 

 correft. It is fuppofed to be hornblende in a capillary 

 form. Haliy. 



Amazon-Stone, gi-een fclfpar from South America, 

 which is cut and poliftied, and fold under that name, be- 

 caufe it is found in rolled pieces on the banks of the river 

 of the Amazons. 



Amber, IVhite and Yellow. The white amber is of a 

 ftraw-yellow or yellowifh-white colour. It occurs maffive, 

 and fometimes inclofed in the yellow amber ; it is lefs tranf- 

 parent than yellow amber. See Amber. 



Amethyst, a variety of cryftallized quartz. (See 

 Quartz, and Amethyst.) Werner divides amethyfts into 

 two fub-fpecies, common and fibrous. The prevailing 

 colour of the amethyil is violet-blue of different degrees 

 of intenfity ; but it is fometimes plum-blue and brownifh- 

 black ; alfo grey, olive-green, and piftachio-green, which 



Analcime. See Zeolite. 



Anatase, or Odahiedrite, Titane anatart, Haiiy. See 

 Titanium. 



Andalusite, Feldfpath aphyre, Haiiy, is of a flefh- 

 red colour, fometimes inclining to pearl grey ; it occurs 

 maflive or cryftallized in reftangular four-fided prifms, with 

 the terminal edges and angles fometimes truncated. The 

 ftru6ture is imperfeftly lamellar, with a double rectangular 

 cleavage, parallel with the lateral planes of the prifm. It is 

 tranflucent ; it fcratches quartz with eafe, but is rather eafily 

 frangible. The fpecific gravity is 3.16. Before the blow- 

 pipe it becomes white, but is infufible. According to Vauque- 

 hn, the conftituent parts are, 



Silex .... 



Alumine .... 



Potafh .... 



Oxyd of iron - - 



32 



8 

 2 



94 



It occurs in veins in granite, gneifs, and mica-flate, along 

 with felfpar, quartz, mica, and fchorl. It was firft found 

 in the province of Andalufia. It has fince been found 

 in Aberdeenfhire. The cryftals are generally middle-fized 

 or fmall, and occur imbedded. It is diftinguifhed from 

 felfpar by its greater hardnefs, weight, and infufibility ; and 

 from corundum by its double reftangular cleavage, and its 

 inferior fpecific gravity. 



Anhydrite, or Anhydrous Gypfum, a fpecies of gyp- 

 fiim which contains fcarcely a trace of water in its compo- 

 fition, and is much harder than common gypfum ; the latter 



(fee 



