500 



MINERALOGY. 



Oryctogno- 3. RiioM&oiiUL CALAMINE, Jameson. Galmei, Wer- U*cs. Both prismatic and rhomboidal calamine, Oryctogns- 



ner. Rhomboedrischer Zink-Baryt, 



when purified and rousted, Pre used for the fabrication *)' 



Rhomboid about 110. Cleavage in the direction of of brass which is a compound of zinc and copper ; and 



the pure met J is also employed for a variety of other 

 pui puses. 



GENUS IV. TUNGSTEN , or SCHEELIUM t. 



Sparry 

 vboii'tx 

 calamine. 



the planes of the rhomboid. Hardness = 5.0. Sp. gr. 

 = *2, 4.4. 



This species is divided into three subspecies, viz. 

 Sparry Rhomboidal Calamine, Compact Rhomboidal 

 Calamine, and Earthy Rhomboidal Calamine. 



FIRST SUBSPECIES. 



SPARRY RHOMBOIDAL CALAMINE, Jameson. Spathi- 

 ger Galmei. Karsten. 



External Characters. Colours white, grey, green, and 

 brown. Occurs massive, botryoidal, reniform stalac- 

 titic. tabular, cellular ; also in distinct concretions, 

 which are prismatic, granular, and curved lamellar; and 

 sometimes crystallized. Internally shining and pearly. 

 Fragments rhomboidal. Alternates from semitranspa- 

 rent to opaque. 



Chemical Characters. It dissolves with effervescence 

 in muriatic acid ; it is infusible ; loses about 34 per cent. 

 by ignition. 



Constituent Parts. 



Derbyshire. Somersetshire. 



Oxide of Zinc, . 6.5.2 64 8 



Carbonic Acid, . 34 K 100 358 100 



Smithson, in Phil. Trans. Part i. for 1803. 



SECOND SUBSPECIES. 



COMPACT RHOMBOIDAL CALAMINE, Jameson.^Ge 

 meiner Galmei, Kirxlen. 



External Characters. Colours grey, yellow, and yel- 

 lowish-brown. Occurs massive, disseminated, corroded, 

 reniform, stalactitic. and cellular; also in concentric 

 curved lamellar concretions. Karely in supposititious 

 crystals, or incrusting other crystals. Internally dull, 

 or very feebly glimmering and resinous. Fracture 

 coarse-grained uneven, fine splintery, even, and flat con- 

 choidal. Opaque, or feebly translucent on the edges 



Chemical C/iuraclers. The same as in the preceding 

 subspecies. 



THIRD SUBSPECIES. 



Earthy EARTHY RHOMBOIDAL CALAMINE, Jameson. Zink- 



rhomboidal blu ' ne ' Kartell. 



calamine. External Characters Colour white, sometimes with a 

 yellowish-brownish exterior Occurs massive, dissemi- 

 nated, botryoidal, flat, reniform, and with impressions. 

 Internally dull. Fracture fine earthy. Opaque. Yields 

 to the nail. Adheres to the tongue. 



Chemical Characters. The same as in the first sub- 

 species. 



Rleiberg in Carinthia. 



Constituent Parts Oxide of Zinc, 71.4 

 Carbonic Acid, 13.5 

 Water, . 15.1 100.0 



Smithson, in Phil. Irans. Part 1. for 1803. 

 Gengnostic Situ'ition of the Spccirs. It occurs in 

 beds, nests, filling U p or lining hollows, in transition 

 limestone, and in secondary or floetz limestone, and 

 conglomerate rock ; also in veins 



TUNG. 



8TEN. 



calamine. 



Hardness = 4.0 Tur,j;te 

 or Schee- 



viz. Pyramidal lium - 



Geographic tiituatinu of the Species Europe. It oc- rocks. 



Scheel Baryt, M:,hs. 



One axis. Cleavage pyramidal. 

 4.5. .^p. gr = fi.O ri.l. 



Tin's genus contains one species 

 Tungsten. 



1. PYRAMIDAL TUNGSTEN, Jameson. Pyramidaler 

 gcheel-Baryt, Mohs. Schwerstein, Werner. 



Pyramid = 107 26' 113 36'. The most distinct Pyramidal 

 cleavage is that parallel with the planes of the tungsten. 

 primitive pyramid ; another less distinct in which the 

 planes are parallel with the sides of an acute pyramid, 

 (100 8'; 130 20'); and a third, the least distinct, 

 parallel with the common base of the pyramid. 



External Characters. White is the principal colour of 

 thismineral. The following varieties of colour also some- 

 times occur, viz. brown, which somstimes inclines to 

 orange-yellow and hyacinth-red. Occurs massive, dis- 

 seminated, also in distinct concretions, which arc gra- 

 nular, seldomer wedge-shaped prismatic, and these 

 latter traversed by others which are curved lamellar. 

 Sometimes crystallized. The following are the second- 

 ary forms : 



1. The primitive figure, in which the angles of the 

 common base are flatly bevelled, and the bevelling 

 planes set on the lateral edges. 2. Very acute double 

 four-sided pyramid, in which the lateral planes of the 

 one are set on the lateral planes of the other. 3. Flat 

 double four-sided pyramid. 



Crystals middle-sized, small and very small ; they 

 are always superimposed, sometimes in single crystals, 

 sometimes in druses. Lateral planes of the crystals 

 generally smooth ; planes of the first pyramids slightly 

 streaked; shining and splendent; lustre inclines to 

 adarrantine. Internally shining, lustre resinous, some- 

 times inclining to adamantine. Fracture coarse, or small- 

 grained uneven, passing into imperfect conchoids!. 

 Fragments indeterminate angular, rather blunt-edged. 

 More or less translucent, seldom semitransparent. Ra- 

 ther brittle, easily frangible. 



Chemical Characters It crackles before the blowpipe 

 and becomes opaque, but does not melt ; with bor-ix it 

 forms a transparent or opaque white glass, according 

 to the proportions of each. 



Cornwall. 



Constit. Part*. Oxide of Tungsten 7.5 5 

 Lime, . . U 70 

 Silica, . 1.56 



Oxide of 'ron, 1.25 



Oxide of Mangsnese, 0.75 97 45 



Geognostic Situation. It occurs along with tinstone, 

 magnetic iron-ore, and brown iron-ore, in primitive 



curs in the Mendip Hills, at Shipham, near Cross, So- 

 mersetshire; at Allonhcad in Durham ; at Holy well, 

 and elsewhere in Flintshire ; and in Derbyshire. 



Geographic Situation. It occurs along w : th wolfram 

 and tin-ore at Pengilly in ttreage in Cornwall : at Bisp- 

 berg in Sweden, in a bed of magnetic iron- ore. 



The name Tungiten was given to this mineral by the Swedes, on account of its great weight. 



t Werner gave the name Sc/ieelc to this genus, in honour of the illustrious chemist Scheele, who discovered the peculiar metal whwh 

 characterises it. 



