DEMANT. 



■ Anahjsis, of reddish-brown specimen, by 

 Dumont i 



Phosphoric acid . . . 16-04 

 Peroxide of iron . . , 34-20 

 Water 48-30 



100-00 

 BB changes colour, decrepitates, and fuses 

 to a grey magnetic globule. 



Locality. Berneau, near Vise', in Belgium. 

 Name. After Mons. Delvaux. 

 Brit. Mus., Case 57. 

 Demant, Werner. See Diamond. 

 Demant Spath, Emerlhig. See Corundum. 

 Demidoffite, Demidovite, Nordens- 

 hiold. A mineral mixed with the Malachite 

 of Nischne Tagilsk, which it covers in deli- 

 cate layers. Surface splendent. Slightly 

 earthy. Colour sky-blue, sometimes with 

 a tinge of green. Translucent at the edges. 

 H. 2. S.G. 2-25. 

 A.nalysis : 



Silica 31-53 



Alumina .... 0*53 

 Oxide of copper . . . 33-14 

 Magnesia .... 3-15 

 Phosphoric acid . . . 10-22 

 Water 23-03 



101-62 



Localities. Cumberland and Cornwall 

 with quartzose rock and Malachite. Val- 

 paraiso, S. America. 



Name. After Prince Anatole de Demidov. 



Dendrachates ( from livl^h, a tree ; and 

 "A%aT-/i5, Agate), the name given by the 

 ancients to Moss-agate. 



Dent de cochon, De Lisle. See Dog's- 

 tooth spar. 



Dermatin, Breithaupt. Occurs in reniform 

 masses, rarely globular, and in thin coatings 

 or crusts on Serpentine. Colour dark olive- 

 green or liver-brown, with a resinous lustre. 

 Translucent at the edges. Feels greasy. 

 Odour, when breathed upon, argillaceous. 

 Streak yellow, inclining to grey. Fracture 

 conchoidal. PI. 2-0. S.G. 2-136. 



Comp. (Mg, Fe)3 t5i2 + 6H ? 





Analysis by Ficiniis ; 





Silica .... 



. 35-80 



Magnesia . 



. 23-70 



Protoxide of iron . 



. 11-33 



Peroxide of manganese 



. 2-25 



Alumina 



. 0-42 



Lime .... 



. 0-83 



Soda .... 



. 0-50 



Water and carbonic acid 



. 25-20 



100-03 



- DEWEYLITE. 107 



BB splits and becomes somewhat friable, 

 and assumes a darker hue. 



Locality. The serpentine quarry at Wald- 

 heim in Saxony. 



The name is derived from li^f^^, skin, in 

 allusion to its occurrence as an incrustation. 



Descloizite, a. Damour. Rhombic : no 

 cleavage. Colour mostly deep bh-ick ; smal- 

 ler crystals olive, with a chatoyant, bronze 

 lustre. Light brown inclining to red at the 

 edges by transmitted light. The colours 

 are zoned with straw-yellow, reddish-brown 

 and black on surfaces of fracture. H. 3-5. 

 S.G. 5-84. 



Fig. 143. 



Comp. W V = oxide of lead 7-07, 

 vanadic acid 29*3 = 100 0. 



Analysis (mean of two) by A. Damour ; 



Vanadic acid 



. 22-46 



Oxide of lead 



. 54-70 



Oxide of zinc 



. 2-04 



Oxide of copper . 



. 0-90 



Protoxide of manganese 



. 5-32 



Chlorine 



. 0-32 



Peroxide of manganese 



. 6-00 



Peroxide of iron . 



. 1-50 



Sand .... 



. 3-44 



Water .... 



. '2-20 



98-88 

 The zinc, copper, manganese, and iron are 

 considered impurities. 



BB fuses and is partially reduced to a 

 black slag investing a globule of metallic 

 lead. 



Soluble in cold dilute nitric acid. 



Locality. S. America, in small crystals, 

 on a siliceous and ferruginous gangue. 



Name. After Descloiseaux, Crystallo- 

 grapher. 



Desmin, Breithaupt, "| 

 Hausmann, Naumann, > See Stilbite. 



Desmine, Dufrenoy.J 



Deuto-fluate of Cerium. See Fluo- 

 CERiTE or Flucerine. 



Devonite, Fuchs. A name given to 

 Wavellite, in allusion to its having been first 

 discovered in the county of Devon. 



Deweylite, Emmons. An amorphous 

 mineral, bearing some resemblance to gum- 

 arabic. Colour whitish, yellowish, greenish, 

 reddish. Lustre greasy. Translucent. Brit- 



