MI N E R A L G Y. 



551 



Orjttogno- 



Pyramidal 



i or 



VCJUIUD. 



Dodreihc- 

 drilfvnct. 



1'jrcneitf. 



GrouuUrc. 



No pure vitreous lii'tre. If prismatoidal, the hardness 

 is = 7 , and no pure vitreous lustre. Han: 



range- J- If 7.5. it is red or brown. Sp. 



= 1.3 4.3. 



1. P'VH \MIDALGARNET or VESUVIAN, Jameson. Py- 

 ramidal -r Cir.ii.i-, M ,/ts. Vcauvian, Werner. Ido- 

 . 



! 'yramid = 1 29 3V, 74 1 4'. Cleavage 



. of the lateral planes of the prUm ; in 



the direction of the diagonals of the prism ; and also 



in the direction of the terminal planes of the prUm. 



Hardness = fi.J. Sp. gravity = 3.33.4. 



Exl- rial Characters. Colours green and brown. 

 Occurs massive, disseminated, and in granular concre- 

 but more frequently crystallized, in rectangu- 

 lar four-sided prism 8 , variously acuminated, trunca- 

 ted, and bevelled. Lateral planes of the prism are lon- 

 gitudinally ttreaked ; but the truncating and terminal 

 planes are smooth. Externally the crystals are splen- 

 dent ; internally glistening, approaching to shining, 

 and the lustre is vitreo-retinous. Fracture is small- 

 grained uneven. Alternates from translucent to trans- 

 lucent on the edges, and refracts double. 



Chemical Characters Before the blowpipe it melts 

 without addition into a yellowish and faintly translu- 

 cen* glass. Vaurun of Vaurios. 



-Ait. Parti. Silica . . . 35.5 

 Lime . . . 33.0 

 Alumina . . 22.25 



IP of Iron . 7-5 

 Oxide of Manganese 0.25 

 Loss . . . 1.5100 



Klaproth, Bnt. b. ii. *. 32. & 38. 

 "HOtlic and Geographic Situation*. Occurs in 

 various primitive rocks, in Ireland, Italy, Norway, 

 Switzerland, &c. 



..-- At Naples it H cut into ring-stones, and is 

 sold under variou* names: the green- coloured varieties 

 are denominated Volcanic Chrysolite; and the brown, 



nic Hyacinth. 



Obiervatiim. The Egeran of Werner is a variety of 

 this species. 



2. DODECAIIEDHAI. GARNET, Jametnn. 

 Teul.ir. Cleavage dodecahedral. Hardness = 6.5 

 7.5, sp. gravity = S.S 4.3. 



This species contain* nine subspecies, viz. 1. Pyre- 

 neite ; 2. Grossulare ; 3. Melanite ; 1. Pyropc ; 5. Gar- 

 net ; 6. Allochnxtc ; Colophonite ; 8. Cinnamon-stone ; 

 9. Helvm. 



FIRST SUBSPECIES. 



PVBFNF.ITE, Jametnn. Pyrciieit, Werner. 

 External Character* Colour greyii-li-bl.ick. Oc- 

 curs massive, and crystallized in the form of rhomboi- 

 dal dodecahedrons. Externally glistening, inclining to 

 finning, and metallic-tike. 1-nirnally gli-ti-ning and 

 vitreou*. Fracture small-grained uneven. Opaque. 



gnotlic anil Geographic Situation*. Occurs in 

 primitive limestone in the Pic of Lrcs-Lids, near Ba- 

 rege*, in the French Pyrenees. 



SECOND SUBSPECIES. 

 -SULARB, Jumemn. Grossular, Werner. 

 External Charactert. Colour asparagus-green. Crys- 

 tallized in acute double eight-sided pyramids flatly acu- 

 minated on both ex; <y four planes ; the acu- 

 minating plane* let on the alternate edges of the double 

 right lals are smooth. 

 J \u-ri, .1. . internally shining, and lustre re- 

 sinou .'termediale between conchoidal and 

 une\ i-ilucent. 



Gtognnuic and Geographic Situation*. Occurs im- 



bedded in small crystals, along with vesuvian, in a Oryctogno. 



pale greenish-grey claystone, near the river Wilui in ^? i 



Siberia ; also in the Bannat of Temeswar. 



THIRD SUBSPECIES. 



MELANITE, Jameson. Melanit, Werner. Melanite. 



External Characters. Colour velvet-black. Gene- 

 rally crystallized in rhomboidal dodecahedrons, trilli- 

 on the edges. Internally shining, inclining to 

 glistening, and resino-vitreous. Fracture conchoidal. 

 Opaque. 



Gengnottic and Geographic Situations Occurs in 

 primitive and secondary rocks in Italy, Germany, and 

 Norway. 



FOURTH SUBSPECIES. 



PVROPE, Jameson. Pyrope, Werner. Pvrope. 



Ex'ernal Chara lers. Colour dark blood-red. Oc- 

 curs in roundish and angular grains. Lustre splendent, 

 and vitrfo-resinous. Fracture conchoidal. Is tran>pa- 

 rent, and refracts double. 



Gengnotlic and Geographic Situation. It occurs in 

 serpentine and trap, in Bohemia. 



lite This beautiful gem is employed in almost every 



kind of jewellery, and is generally set with a gold foil. 



FIFTH SL-BSPECIES. 



GARNET, Jameton. Garnet. 



This subspecies is divided into two kinds, viz. Pre- 

 cious Garnet and Common Gurnet. 



First Kind. PRECIOUS GARNET, Jameton. EdlerGra- Precious 

 nat. Wemer. e uat ** 



External Characters All the colours of this gem 

 are dark-red, which generally fall into blue. Occurs 

 in roundish grains, and crystallized in rhumnuidal do- 

 decahedrons, and in the form of the leucite. Internally 

 it is shining, bordering on splendent ; and vitreous, 

 inclining slightly to resinous. Fracture conchoidal. 

 Sometime" occurs in lamellar distinct concretions. Al- 

 ternates from completely transparent to translucent. 



Conttit. Parti Silica, . 39.66 



Alumina, . 1966 



Black oxide of Iron, 39.68 

 Oxide of Manganese, 18010080 

 Berzetiiit, in Afhandlinger, vol. iv p. 385. 

 Chemical Character. Before the blowpipe it melts 

 pretty easily into a black scoria or enamel. 



Gfognoslic and Geographic Situation.!. Occurs imbed- 

 ded in primitive rocks, in Scotland, England, Ireland, 

 Germany, Norway, Sweden, and many other countries. 

 l'*e. This beautiful gem is not so highly valued at 

 present as it was a century ago. The larger kinds are 

 used as ring-stones, and, after cutting and polishing, 

 are set either au jour, or are provided with a silver or 

 violet-bine foil. 



Second Kind. COMMOM GARNET, Jameson. Gemeiner Common 

 Granat, Werner. garnet. 



External Charactert. Brown and green are its most 

 common colours. Occurs most commonly massive : 

 sometimes crystallized, and possesses all the figures of 

 the precious garnet. Occurs in angulo-granular dis- 

 tinct concretions. Lustr nig, very 

 rarely cplendent. Internally lu.-trc ^li^tening, seldom 

 shining, and intermediate between resinous and vitre- 

 ous. Fracture fine-grained uneven, sometimes slightly 

 inclining to imperfect c<>nclioidnl. or to splintery. 



Geognotlic and Geographic Nitualioni. It occurs 

 massive or crystallized in primitive rocks in Scotland, 

 England, Ireland, Norway, Sweden, Germany, Italy, 

 and many other countries. 



L'te. On account of its easy fusibility and richness 

 in iron, it is frequently employed us a mix in smelting 

 rich iron-ores, and as an addition to poor ores. 



