484 



MINERALOGY. 



Oryctogno- worked, and the high polish it receives, it is cut into 



sy- vases, pyramids, and other ornamental articles. The 



>1 ""Y"^*' largest masses, and most beautiful varieties for use, are 



found in Derbyshire, and it is in that county that all 



the ornamental articles of fluor-spar are manufactured. 



It is also used by the metallurgist, as a flux for ores, 



particularly those of iron and copper ; and hence the 



name jluor given to it. The acid it contains has been 



employed in the way of experiment for engraving upon 



glass. 



THIRD SUBSPECIES. 



EARTHY FLUOR, Jameson. Erdiger Fluss, Karsten. 

 Earthy External Characters Colours greyish-white, and 



fluor. violet-blue, and sometimes so deep as almost to ap- 



pear black. Occurs generally in crusts, investing some 

 other mineral. Dull. Earthy. Friable, passing into 

 very soft. 



Constituent Parts. .It is said to be a compound of 

 Lime and fluoric a,cid. 



Geognostic and Geographic Situations It occurs in 

 veins, along with flour-spar, at Beeralston in Devonshire; 

 in limestone, along with fluor spar and arragonite, in 

 Cumberland. 



GENUS V APATITE. 



AATITE. One axis. Cleavage rhomboidal. Hardness=5.0. 

 Sp. gravity =3.1, 3.2. 



1. RHOMBOIDAL APATITE, Jameson Rhomboedri- 

 scher Plus Haloide, Mohs Apatit, Werner. 



Di-rhomboid=131 49', 109 28'. The mostperfect 

 cleavage is parallel with the terminal planes of a six- 

 sided prism ; another less distinct, parallel with the 

 sides of a regular six-sided prism. Hardness=5.0. 



This species is divided into three subspecies, viz. 

 Foliated Apatite, Conchoidal Apatite, and Lamellar 

 Apatite. 



FIRST SUBSPECIES. 



FOLIATED APATITE, Jameson Geminer Apatite, 

 Werner. 



Foliated External Characters Its most frequent colour is 

 Apatite. white ; from greenish-white it passes into mountain- 

 green, celandine-green, like-green, emerald-green, and 

 olive-green. It occurs also red and blue. Sometimes 

 it is pale wine-yellow, and yellowish-brown. Fre- 

 quently several of these colours occur in the same 

 piece. It sometimes occurs massive and disseminated, 

 also in distinct concretions, which are large and small 

 angulo-granular, and sometimes thin and straight 

 lamellar; generally crystallized. Its secondary figures 

 are the six-sided prism, and six-sided table, variously 

 modified by truncations, bevelments, and acumina- 

 tions. The crystals are small, very small, and middle- 

 sized ; and occur sometimes single, sometimes many 

 irregularly superimposed on each other. The lateral 

 planes are seldom smooth, generally longitudinally 

 streaked ; the truncating and acuminating planes are 

 smooth. Externally it is splendent or shining ; inter- 

 nally glistening, and the lustre is resinous. Fracture 

 intermediate between uneven and imperfect Conchoidal. 

 Fragments indeterminate angular, and rather sharp, 

 edged. Generally translucent; seldom nearly trans- 

 parent, when it refracts single. Brittle and easily 

 frangible. 



Physical Characters It becomes electric by heating, 

 and also by being rubbed with woollen cloth. 



Chemical Characters When thrown on glowing 

 coals, it emits a pale grass-green phosphoric light. It 

 dissolves very slowly in the nitric acid, and without 



effervescence. It gradually loses its colour, when heat- Oryetogno- 

 ed before the blowpipe, but its lustre and transparency v **' , 

 are heightened. It is infusible without addition. sp -v < ' 



Constituent Parts. Lime . . 55 



Phosphoric Acid, and trace of Manganese 4-5 100 



Klapralh, Bergm. Journ. 1 788, b. i. s. 269. 



Geognostic Situation It occurs in tin-stone veins, 

 and also imbedded in talc. 



Geographic Situation Europe, -It occurs in yellow 

 foliated talc, and, along with fluor-spar, in the mine 

 called Stena-Gwyn, in St. Stephen's, in Cornwall, also 

 at St. Michael's Mount, God\>lphin-bal in Breage, also 

 in Cornwall ; and in various districts on the Continent 

 of Europe. 



America. It occurs in grains or hexahedral prisms. 

 in granite, near Baltimore in Maryland; in granite 

 and gneiss, along with beryl, garnet, and schorl, at 

 Germantown in Pennsylvania; in iron-pyrites at St. 

 Anthony's Nose, in the Hudson in New York; in gra- 

 nite, at Milford-hills, near New-Haven in Connecticut ,- 

 and at Topsham in Maine, in granite. 



SECOND SUBSPECIES. 



CONCHOIDAL APATITE OR ASPARAGUS STONE, Jame- ConchoidaJ 

 son. Muschlicher Apatit, Hausmann. Spargelstein, 

 Werner. 



External Characters. Colours green and wine-yel- 

 low, bordering on orange-yellow. Also sky-blue, 

 greenish and yellow-grey, and clove-brown. Some, 

 times massive and disseminated, also in distinct con. 

 cretions, which are large granular; but most frequently 

 crystallized, and in the following figures : 



1. Equilateral, longish, six-sided prism, acuminated 

 with six planes, which are set on the lateral planes. 

 2. The same figure, truncated on the lateral edges of 

 the prism. 



Crystals middle-sized, small, and very small ; some- 

 times longitudinally streaked, and sometimes traversed 

 by cross rents. Externally crystals splendent and vi- 

 treous : internally shining, and resinous. Fracture 

 small and imperfect Conchoidal. Fragments rather 

 blunt-edged. Alternates from transparent to translu- 

 cent. In other characters agrees with the foliated 

 apatite. 



Chemical Characters Some varieties of this subspe- 

 cies do not phosphoresce when exposed to heat. 



Constituent Parts. 





From ZiHerthal. 

 Lime, . 53.75 



Phosphoric Acid, 46.25 



Apatite from Uto. 

 Phosphate of Lime, 92.00 

 Carbonate of Lime, 6.00 

 Silica, .. 1.00 



Loss in heating, 0.50 100 



Manganese a trace. Klaproth, Beit. 



99-50 b. iv. s. 197. 



Klaproth, Beit. 



b.v. s. 181. 



Geognoslic and Geographic Situations Europe. 

 It occurs, imbedded in gneiss, near Kincardine in 

 Ross-shire ; also in beds of magnetic ironstone, along 

 with sphene, calcareous-spar, hornblende, quartz, and 

 augite, at Arendal in Norway. 



America. Imbedded in granite at Baltimore ; in 

 gneiss at Gennantown; and in mica-slate in West 

 Greenland. 



THIRD SUBSPECIES. 

 PHOSPHORITE, Jameson. Phosphorit, Werner. Pbospho- 





