CLAY IRON-STONE. 

 Clay Iron-stone. A iuassive form of 

 Siderite rendered impure by an admixture 

 of clay. Most of the iron of this country- 

 is extracted from this ore, which derives an 

 additional value from its occurrence in 

 layers and nodules in the Coal-measure 

 strata. See Black Band. 



M. P. G. Principal floor, Wall-cases 50 to 

 52 (British); 18 and 19 (Foreign); 41 

 (Vancouver's Island;; Upper Gallerv, VVall- 

 case 43, Nos. 134 to 169, 179 to 182"; Wall- 

 case 44. 



Clayite, W. J Taylor. A variety of 

 Galena with about 25 per cent, of Arsenic, 

 Copper, and Antimony, and apparently ana- 

 logous with Steinmannite. Occurs in 

 small cubical crystals, a combination of the 

 tetrahedron with the dodecahedron ; also 

 amoi'phous as a thin coating on a layer of 

 Quartz. Colour and streak blackish-grey. 

 Sectile. H. about 2-5. 



Comp. (Pb, -e-u) (S, As, Sb). 

 Analysis. 



Lead G8-51 



Sulphur .... 822 

 Arsenic . . . . 9'78 



Antimony . . . . 6-54 



Copper 7-67 



Silver trace 



100-72 



BB on charcoal fuses easily, giving reac- 

 tions for lead, arsenic, and antimony, and 

 with soda a brilliant metallic globule which 

 becomes lustreless on cooling. 



Locality. Peru. 



Name. After the Hon. J. R. Cla3% U.S. 

 Minister in Peru, and J", A. Clay, of Phila- 

 delphia. 



Cleavelandite, Broohe §- Levy. See 

 Albite. Named after Pai-ker Cleaveland, 

 Lecturer on Chemistry and Mineralogy, 

 Bowdoin College, U.S. 



Brit. Mus., Case 30. 



Clkiophane, Nuttall. A white ti-anspa- 

 rent variety of Blende. It has been found 

 at Fowey Consol Mines, in Cornwall. 



Clingmanite, Silliman. See Margarite. 

 The name Avas proposed (after that of the 

 Hon. T. L. Clingman), for a distinct species 

 in consequence of an incorrect determina- 

 tion of the silica in the anah'sis. 



Clinoohlore, W. p. Blake. Rhombic 

 and hemihedral. Occurs in large crystals, 

 having generally a rhombohedral aspect, 

 and in plates with a micaceous structure. 

 Colour olive-green with a somewhat pearly 

 lustre. Transparent in thin plates. Some"- 

 v/hat elastic. Optically biaxial ; in com- 

 pound crystals there is a second pair of 



CLTNOCLASE. 



87 



optical axes making 60° with the other. 

 H. 2 to 2-25. S.G. 2-7. 



Comp. 5k3 fei+SAL fci' + 12H= (pi3 + 



I'it) Si + 1-5 H= silica 32-6, alumina 17-9, 

 magnesia 36 6, water 12*9 = 100. 



Analysis from Bavaria, bv v. Kobell: 

 Silica ...".. 33-49 

 Alumina .... 15-37 

 Peroxide of iron . . . 2-30 

 Oxide of chrome . . . 0*55 

 Magnesia . . . .32-94 

 Protoxide of iron . . 4-25 

 Water 11'50 



100-40 



BB like Chlorite: exhibits traces of fu- 

 sion at the edges. 



Localities. Lengast in Bavaria, in large 

 crystals and plates, with Serpentine. Ach- 

 matowsk in Siberia ; and in the United 

 States near Westchester, and Unionville, 

 Chester co., Penns^dvania. 



M. Descloiseaux refers to this species 

 Tabergite, and the hexagonal Chlorite of 

 Pfitsch, Pfunders, and Zillerthal in the 

 Tjn'ol, which occurs in bip3a-amidal hexa- 

 gonal compound crystals ; and the ChIoi"ite 

 of Traversella is also, according to him, a 

 talcose Clinochlore. 



Clinoclase. Greg Sf Lettsnm. Arseniate 

 of copper. Oblique. Rarely occurs distinctly 

 crj^stallized in small oblique rhombic prisms. 

 Colour "dark verdigris-green inclining to 

 blue ; also dark-blue. Lustre pearly on 

 cleavage planes, elsewhere vitreous to re- 

 sinous. Streak verdigris-green. Translu- 

 cent at the edges. H. 2-5 to 3. S.G. 4-2 to 

 4-36. 



Fig. 118. 



Fig. 119. 



Comp. Cu5 As + 3Cu H = oxide of copper 

 62-7, arsenic acid 30-2, water 7-1 = 100. 

 Analysis from Cornwall, by Ramvielsberg : 

 Arsenic acid .... 29-71 

 Phosphoric acid . . .0-64 

 Oxide of copper . . . 60-00 



Silica 1-12 



Peroxide of iron . . .0 39 



Lime 0*50 



Water 7 64 



100-00 



g4 



