10 



Fig. 8. 



ALVITE. 



Fig. 9. 



Comp. Telluride of lead or Pb Te = 

 61-7, tellurium 38-3 = 100, 



Analysis by G. Rose. 



Lead . . , . 60-35 

 Tellurium .... 38-37 

 Silver 1-28 



lead 



100-00 

 BB colours the flame blue: in the inner 

 flame volatilizes, except a minute globule 

 of silver. Soluble in nitric acid. 



Locality. The Savodinsky mine, near 

 Barnaoul, in the Altai ; mixed with telluric 

 silver. 



AL^aTE, David Forbes ^ F. Dalill. Crjs- 

 tallizes like Zircon. Colovir reddish-brown, 

 becoming greyish-brown on alteration. 

 Opaque; translucent at the edges. Lustre 

 greasv. Fracture conchoidal. H. 5"5. S.G. 

 3-40 to 3-6. 



BB in the platina forceps infusible : be- 

 comes paler by heat. With borax yields a 

 yellow glass, which becomes colourless on 

 cooling. 



Comp. An approximative analysis shoAvs 

 it to consist chie% of silica, yttria, thorina( ?), 

 alumina, and glucina, peroxide of iron and 

 water. 



Localities. Helle and Karesto in Norway. 



Alum. Under this name are comprised 

 several compounds which have the general 



formula R S + Al fe5 + 24 H, (K represent- 

 ing different bases, as potash, soda, mag- 

 nesia, protoxide of manganese, &c.) which 

 are described under their respective names. 

 All these compounds crystallize in octa- 

 hedrons, but they usually occur in nature in 

 fibrous masses, or as a mealy efHorescence, 

 with a sweetish astringent taste, more or 

 less resembling that of common alum. It 

 is soluble in from 16 to 20 times its weight 

 of cold water, and in little more than its 

 own weight of boiling water. On exposure 

 to heat, it melts easily in its own water of 

 crystallization, and froths up in a remark- 

 able way, and by contirmance of heat it is 

 converted into a Avhite spongy mass. Alum 

 is used largely in the manufacture of leather 

 and paper, as a mordant in dyeing, in me- 

 dicine, for preserving animal substances from 

 putrefaction, and for various other purposes. 

 The. alum of commerce is made either from 

 clay or from alum-slate or shale. Much of 



ALUMSTONE. 



the Dorsetshire pipe-clay, v.'hich is not of 

 sufficiently good quality for use in the 

 potteries, is converted into alum by being 

 treated with sulphuric acid. The sulphate 

 of alumina which is thus formed, being lixi- 

 viated Avith Avater, potash salts are added, 

 and crystals of alum are ultimately obtained 

 by evaporation. At Whitby, in Yorkshire, 

 the -alum-shale is mixed with fuel and set 

 on fire ; the residue is lixiviated Avith Avater, 

 and purified by subsequent CA^aporation ; 

 potash salts are added, and crystallized alum 

 is finally formed. The best alum is made from 

 the Alum-stone of Tolfa, near Civita Vecchia. 



Alum, Nicol, PldlUps. Native alum. See 

 Potaspi-Alum. 



AlumineFluateeAlcaline, Haily. See 

 Cryolite. 



Alumlne Fluatee Siliceuse, Haiiy. See 

 Topaz. 



Alumine Hydratee Silicifkre, Levy. 

 Siliciferous hj^drate of alumina. 



Alumine- HYDRO -phosphatee, Haiiy. 

 See Wavellite. 



Alumine Magnesiee, Haily. See Spinel. 



Alumine sous-sulfatee. See Web- 



STERITE. 



Alumine Sous-sulfatee Alcaline, 

 Haily. See Alumstone. 

 Alumine Sulfatee, Haily. ^ See 

 Alumine Sulfates Alca- > Aluno- 

 LINE, Haiiy. J gene. 



Aluminilite, La Metherie. See Alum- 

 stone. 



Aluminitk, Jameson. See Websterite. 

 Alumocalcite, Phillips, Breithaupt. An 

 impure Opal of a milk-Avhite colour inclin- 

 ing to blue, and containing six per cent, of 

 lime. Streak Avhite. Fracture conchoidal. 

 Adheres strongh' to the moistened lip. Maj' 

 be crushed betAveen the fingers. S.G. 2*174. 

 Analysis by Kersten : 



Silica 86-60 



Alumina .... 2*25 



Lime, 6-25 



Water 4-00 



99-10 



BB in the platina forceps becomes opaque 

 and grey-coloured. With borax forms a 

 colourless glass. Forms a transparent jelly 

 in concentrated muriatic acid. 



Locality. Eibenstock, in Saxony ; in clefts 

 in veins of ironstone. 



Alumocalcite Avas formerly considered to 

 be a decomposed Opal. 



Brit. Mus., Case 25. 



Alumstone, Phillips, occurs massive and 

 crystallized in modifications of an obtuse 

 rhomboid. The crystals are minute, shining, 



