.S ALLEMONTITE.' 



Brittle. Fracture uneven, passing into small 



conchoidal. H. 6. S.G. 2-86 to 2-9. 



(<7=^. 



Fig. 6. 



Camp. 3K3 Si + 2-R Si + 10 H. 



Anah/sis bv D. Forbes, from Naes Mine : 

 Silica " . . . .31-03 

 Alumina .... 9-29 

 Glucina .... 3-71 

 Protoxide of iron . . . 20-68 

 Protoxide of manganese . 0*07 

 Protoxide of cerimn . . 6*74 

 Oxide of lanthanium . . 4-35 

 Yttria . . . .1-02 



Lime 6-G8 



Magnesia . . . .2-06 

 Potash .... 0-90 



Soda 0-56 



Oxide of copper . . . trace 

 Water 12-24 



99-33 

 JBB on charcoal swells up, becomes brown- 

 ish-yellow and fuses to a black (somewhat 

 magnetic) glass. 



Localities. — Scotch. 1 mile west of New 

 Abbey, near Crifiel, E. Kirkcudbrightshire ; 

 in syenite.— Foreign. Norway ; at Naes 

 Mine about 10 miles east of Arendal ; Jotun 

 Fjeld, in porph^-ry : Snarum, with Albite. 

 Greenland, in granite. Plauensche Grund, 

 near Dresden, in Saxony. Near Suhl in the 

 Thuringerwald, in granite. Moriah, Essex 

 CO., New York, with Lanthanite, at the junc- 

 tion of the Sauford magnetic iron with the 

 granite walls. 



Name. After Thomas Allan, of Edinburgh, 

 by whom it was first noticed as a distinct 

 species. 



Brit. Mus., Case 38. 



Allemontite. a name given to arsenical 

 antimony, found at Allemont in Dauphiny. 



Atialysis by. Rammelsberg : 



Arsenic 62-15 



Antimony .... 37-85 



100-00 

 Alley Stone. See Websterite. 

 Allochroite, a fine-grained, massive va- 

 riety of iron-Garnet of a greyish, dingy 

 j-ellow, or reddish colour. Opaque. Frac- 

 ture uneven. H. not so hard as Quartz, but 

 strikes fire with steel. S.G. 3-7 to 4-21. 

 BB behaves like Melanite. 



ALLOPHANE. 



Locality. Norway; principally in an iron- 

 mine near Drammea. 



Name. From aWo? other, and %?»/«, colour ; 

 in allusion to its variety of colours. 



Brit. Mus., Case 36. 



Allogonite, Breithaupt. See Herde- 



RITE. 



Allomorpitite, Breitaaupt. (From aXXo;, 

 other, and fM?<P'>,,form), A variety of Barytes 

 found in scaly masses in Unterwirbach near 

 Rudolstadt iii Schwarzburg. According to 

 Gerngross it contains 1-9 per cent, of sul- 

 phate of limoi^as impurity. 



Allophane. Occurs reniform, massive, 

 encrusting ; occasionally almost pulverulent. 

 Colour pale blue, sometimes green, brown, 

 yellow or colourless. Translucent. Lustre, 

 vitreous or resinous ; internally splendent 

 and waxy. Streak white. Very brittle. 

 Fracture iiat conchoidal and shining. Ad- 

 heres to the tongue. H. 3. S.G. 1*76 to 1-89. 



Comp. Hydrated silicate of alvimina, or 



A13 Si2+ 15H. = silica 24-22, alumina 40-39 



water 35-39 = 100. 





Analysis by A. B. Northcote, from Wool- 

 wich ; 



Silica 



. 20-50 



Alumina 



. 31-34 



Protoxide of iron 



. 0-31 



Lime . 



. 1-92 



Carbonic acid 



. 2-73 



Water 



. 42-91 



99-71 

 BB soon loses colour, and becomes pulver- 

 ulent, causing some intumescence and ting- 

 ing the flame green. Alone infusible ; with 

 borax fuses readily to a transparent colour- 

 less glass. Dissolves perfectly in dihite 

 acids ; when digested in concentrated acids, 

 leaves a silicious jellj'. 



Localities. Allophane has been lately ob- 

 served at the chalk-pits at New Charlton, 

 near Woolwich, Kent, by the students of the 

 Government School of Mines, and determined 

 by them in the laboratory of Dr. Percy. It 

 occurs abundantly, of a honey-yellow colour, 

 in the chalk of Beauvais in France ; also lin- 

 ing irregular cavities in a kind of marl at 

 Saalfield in Thuringia, Schneeberg in Sax- 

 ony, Vise in Belgium and elsewhere. At 

 Richmond, Massachusetts, U.S., it occurs 

 with Gibbsite, forming a hyaline crust, scaly 

 or compact in structure, and brittle ; also, at 

 the Bristol copper mine, Connecticut, U.S. 



Name. From kXXo?, other, and i?«/v<w, to ap- 

 pear ; in allusion to its change of appearance 

 under the blowpipe. 



Brit. Mus., Case 26. 



