ALUNITE. 



and sometimes brownish externally. Colour 

 white, also greyish or reddish. Transparent 

 to subtranslucent. Lustre vitreous or pearly. 

 Streak white. Brittle. Fracture flat con- 

 choidal, uneven ; of massive varieties, splin- 

 terv, occasionally earthy. H. 3-5 to 4. S.G. 

 2-58 to 2-78. 



AMBER. 



U 



Fig. 10. 



Fig. 11. 



Comp. KS + oAl S + 9H. 



Analysis hyCordier, of crystals from Tolfa ; 

 Alumina .... 39-65 

 Sulphuric acid . . . 35-50 



Potash 1002 



Water 14-83 



100-00 



5'^ decrepitates and is infusible alone and 

 with soda: with borax forms a colourless 

 glass. 



Soluble in sulphuric acid, when reduced 

 to powder. Insoluble in water, but after 

 gentle ignition, gives up alum to it, the ex- 

 cess of alumina remaining undissolved. 



Localities, Tolfa, near Civita Vecchia, in 

 the Papal States. Musay and Bereghszasz, 

 in Hungary. ]Milo, Argentiera, in the 

 Grecian Archipelago. The Island of Nevis. 

 Pic de Sancy, in France. Elizabethpol, in 

 Georgia. Silesia, in a eoal-bed. 



Much of the best alum of commerce is 

 procured from Alumstone by repeated roast- 

 ings, washings, and finally crystallizing by 

 evaporation. Some of the Hungarian va- 

 rieties are so hard and compact as to be 

 used for millstones. 



Brit. Mus., Case 55. 



31. P. G. Upper gallery, table-case B, 

 in recess 6, Nos. 179 to 186. 



Alun-ammoniacal, Dufrenoy. See Am- 

 monia-alum. 



Alun de Plume, Dufrenoy, See Halo- 



TEICHITE. 



Alun de Rome, the commercial name for 

 alum made at Tolfa. See Alum -stone. 



Alun-magnesien, Dufrenoy. See Mag- 

 nesia-alum. 



Alun Sodifere, Dufrenoy. See Soda 

 Alum. 



Alunite, Necker. See Alumstone., 



Alunogene, Beudunt, Dana, is a hy- 

 drous sulphate of alumina, composed, 

 when pure, of alumina 15-42, sulphuric acid 

 35-99, water 48-69 = 100-00, corresponding 



I oetj 

 I Native 

 , j AaiAL- 

 J gam. 



Amansite 

 Amantice 

 Amausite, Dufrenoy ■{ 

 Amautite 

 Amauzite 



to the formula Al S^ + 18 H. It occurs gene- 

 rally in delicate fibrous masses or crusts, 

 either white or tinged with yellow or red, 

 when impure. Translucent. 'Lustre silky. 

 Taste like that of common alum. LI. 1-5 to 

 2. S.G. 1-6 to 1-8. 



BE intumesces and fuses easily. Very so- 

 luble. 



Localities. It occurs at Araya near Cu- 

 mana ; Socono ; Copiapo, in Chili, and other 

 parts of South America; in numerous places 

 in the United States ; at Adelaide, in New 

 South Wales, &c. &c. 



Alunogen results from volcanic action, 

 and the decomposition of Pyrites in shales. 

 Amalgam, Dana. ') See 



Amalgame, Necker. | Native 



Amalgam e Natif d'Argent, 



La Metherie. 

 Amalgame d'Ok. See Elect'rum. 



'A variet}' of com- 

 pact Felspar (Or- 

 thoclase) from M- 

 delfors in Sweden. 

 Colour clear grey 

 passing into grey- 

 ish-white. Frac- 

 ture perfect con- 

 choidal. 



Amazon Stone. A bluish-green variety 

 of Felspar (Orthoclase). It is slightly trans- 

 lucent at the edges, and possesses a consi- 

 derable amount of varying lustre. The 

 stone brought from Lake Baikal in Siberia 

 is sometimes, though rarely, in pieces suffi- 

 ciently large to be made into small vases 

 and other ornaments; and, when well cut, 

 it forms an Aventurine composed of silvery 

 spangles in a green base. The verdigris- 

 green variety found on the east side of Lake 

 Ilmen is coloured bv copper. 

 Brit. Mus., Case 30. 

 3L P. G. Horse-shoe Case, No. 955. 

 Amber is found in irregular masses of all 

 shades of 3^ellow, from the palest primrose to 

 the deepest orange, sometimes brown. It is 

 brittle, yields readily to the knife, affordmg 

 a white streak, and breaks with a fracture 

 which is more or less perfecth' eonchoidal. 

 It varies from perfect transparency to com- 

 plete opacity, sometimes, but rarely, being 

 nearly as white as ivory, and has a vitreous 

 or resinous lustre. H. 2 to 2*5 S.G. 1*08. 



Comp. C10H8 = carbon 78 96, hydro- 

 gen 10-51, oxygen 10*52. Burns readily 

 with a yellow flame, emitting an agreeable 

 odour, and leaves a black, shining, light;, 

 carbonaceous residue. Becomes negatively 

 electric by friction. Soluble in alcohol. 



