CASSITEROTANTALITE. 

 3I.P.G. Principal floor, Wall-cases, 8 

 and 25 to 27 (British) ; 20 (Foreign) ; 

 39 (E. Indies) ; 37 (Victoria and Austra- 

 lia). 



Cassiterite may be^ distinguished from 

 Wolfram by its greater hardness, by its 

 giving sparks with steel and by its streak, 

 which is grevish - white, but reddish - 

 brown in Wolfram. From Blende it may 

 be known by its greater hardness and un- 

 even fracture. 



Tin Ore is met with in veins traversing 

 granite, gneiss, mica- or clay-slate and por- 

 phyry. 



CASSITEROTANTALITE. Hausmann. A 

 variety of Tantalite from Finbo and Broddbo, 

 in Sweden, containing much oxide of tin, as 

 a mechanical mixture. S.G. 6-2 to 6*5. 

 Analysis from Broddbo, by Berzelius ; 

 Tantalic acid . . . 66-35 

 Peroxide of iron . . . 11'07 

 Peroxide of manganese . 6*60 

 Oxide of tin. . . . 8-40 

 Tungstic acid . . . 6-12 

 Lime 1*50 



100-19 

 Castelxaudite, Dmnoiir. A variety of 

 Xenotime, found in imperfect crystals, and 

 irregular grains, in the diamond-sands of 

 Bahia, in the Brazils. It varies in colour 

 from greyish-white to pale yellow, and has 

 a greasy adamantine lustre. Hardness 

 greater than Fluor, but scratched by a steel 

 point. 



Castor. A mineral discovered by Breit- 

 haupt; probably a variety of Petalite, 

 which it resembles in hardness, density, and 

 the direction of its two planes of cleavage. 

 Primary form a moditied rhombic prism. 

 Colourless, and transparent, with a high 

 glossy lustre. H. 8*25 to 8-5. S.G. 2-39. 



Comp. Li Si + 2(A1 2bi). 



Analysis by Plattner : 



Silica 78-01 



Alumina . . . 18*86 



Lithia 2-76 



Peroxide of iron . . .0-61 



100-24 

 BB in thin laminae, fuses with difficulty 



to a transparent, colourless globule ; imparts 



an intense carmine colour to the outer 



flame. 



Locality- Elba, in attached crystals in 



granite with an allied mineral, which has 



been named Pollux. 

 Brit. Mus., Case 30. 



CAT'S EYE. 67 



Cat Sapphire. Blackish or greenish- 

 blue varieties of Oriental Sapphire ; often not 

 transparent. 



Cat Silver. An old German mining 

 term for Mica. 



Catapleiite. a mineral of a pale yel- 

 lowish-brown colour, occurring in imper- 

 fect hexagonal crystals, with a perfect basal 

 cleavage. Lustre nearly dull. Slightly 

 vitreous on fractured surfaces. Opaque. 

 Streak Isabella-yellow. H. near 6. S.G. 2-8. 



Comp. R3 Si2 + 2^r Si2 + 6H. 



Analysis by Sjogren : 



Silica .... 46-83 



Zirccnia .... 29-81 

 Alumina . . . . 0'45 



Soda 10-83 



Lime 3-61 



Peroxide of iron . . . 0-63 

 Water 8-86 



101-02 



BB in the platinum forceps, fuses easily 

 to a white enamel ; with borax forms a 

 clear colourless glass. 



Locality. The island of Lamo, near Bre- 

 vig, in Norrv^ay. 



Cat's Eye. A variety of Chalcedonic 

 Quartz, usually of a yellowish, greenish, 

 ash-grey, or yellowish-brown colour; also, 

 hair-brown and hyacinth-red; sometimes 

 olive-green and blackish. It occurs mas- 

 sive and in roundish pieces, rarely exceed- 

 ing a hazel-nut in size, generally much 

 smaller. Commonly more or less translucent, 

 but sometimes perfectly transparent. Easily 

 broken. Fracture small, and imperfectly 

 conchoidal, with a shining lustre between 

 vitreous and resinous. 



BB it loses lustre and transparency on 

 exposure to a strong heat, and in small 

 fragments is fusible, though with difficulty. 



Localities. Ceylon ; the coast of Malabar ; 

 the Harz ; Bavaria ; Sanzawa, in Bohemia. 

 A pale green variety occurs with Epidote in 

 the vale of Llanberis, Caernarvonshire ; also 

 in Scotland. 



Brit. Mus., Case 22. 



M.P.G. Horse-shoe Case, No. 514. 



When cut in high cahochon, in which state 

 it is generally brought to this country, it 

 displays a peculiar opalescence or floating 

 lustre (resembling the contracted pupil of a 

 cat's eye when held towards the light), 

 which is supposed to be caused by the pre- 

 sence of small parallel fibres of Asbestos. 

 It is mostly used as a ring-stone. Of the 

 opaque varieties the red and almost white 

 f2 



