u . 

 <_> i 



MI NEK 



External Characters. Colours red, yellow, and grey. 

 Occurs massive. Internally lustre shining, approach- 

 ing to splendent, and intermediate between vitreous 

 and resinous. Fracture perfect conchoidal, and some- 

 times rather flat conchoidal. Opaque, and sometimes 

 feebly translucent on the edges. 



Geognoslic ana Geographic Situations. It is found 

 in large and small pieces in porphyry, near Telko- 

 banya and Tokay in Hungary, and in other parts of 

 Europe. 



Seventh A'iW._ WOOD- OPAL, Jameson. Holx-Opal, 

 Werner. 



Eilernal Characters Occurs most commonly white, 

 grey, or brown, and sometimes also black. Occurs in 

 pieces which have the shape of branches and stems. 

 Internally lustre shining, and sometimes splendent, 

 glistening, or glimmering. Cross fracture conchoidal ; 

 the longitudinal fracture sometimes modified by the 

 remaining fibrous woody texture. More or less trans- 

 lucent ; sometimes only translucent on the edges. 



inotlic and Geographic Situations. It is found 

 in alluvial land at Zastravia in Hungary ; and is said 

 to occur in secondary trap rocks in Transylvania. 



-,. It is cut into plates, and is then used for 

 snuff-boxes, and other ornamental articles. 

 FOURTH SUBSPECIES. 



Menil.tr. McMLlTE, Jameson. 



F,rsi Kind BROWN MENILITE, Jameson. Brauner 



Menilite, Hoffmann. 



External Characters. Colour chesnut-browp. On 

 the surface sometimes of a bluish colour. Occurs al- 

 ways tuberose. External surface rough and dull ; in- 

 ternally faintly glistening, and lustre intermediate be- 

 tween resinous and vitreous. Fracture very flat con- 

 cboidal. Translucent on the edges. 



Const. Parts. Silica, . . . 85.5 



Alumina, . . . 1.0 



Lime, . . - 0.5 



Oxide of iron, . 0.5 



Water, aud Carbonaceous Matter, 1 1.0 



Klaproth, Beit. b. ii. . 169- 98.5 



Geognostic and Geographic Situations ft has hith- 

 erto been found only at Mi-nil Montant, near Paris, 

 where it occurs imbedded in adhesive-slate, in the 

 : manner as flint is in chalk. 







Traiwlu. 

 cent l)b . 



Brown 

 Mrnilitr. 



FIFTH SUBSPECIES. 

 , .fameton. Obsidian, Werner. 

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

 lucent Obsidian. Transparent O'.i-i'lian. 



T/ Kind TRANSLUCENT OBSIDIAN, Jameson. 

 Dtirrhscheincndcr Obsidian, llmnnann. 



External Characters. Colours black, grey, and green. 

 Occurs massive, internally splendent, seldom shining, 

 and lustre vitreom. Fracture conchoidal. Alternates 

 from translucent to translucent on the edges. Very 

 brittle. Easily frangible. Streak grey. 



> m : cal Characters. The black obsidian of Ice- 

 land, according to Da Camara, on charcoal, before the 

 blowpipe, melt* into a pale ash-grey, imperfect vesicu- 

 lur glass. 



American. 



Const. Parts. Silica, . . 72.0 



Alumina, . . 12.5 



Natron nd Potash, . 10.0 



ie, . . 0.0 



Oxide of Iron and Manganese, 2.0 



Collet- Descotils. 96..I 



Geognoitic Situation. This mineral occurs in beds, 



Pitehstone. 



A L O G Y. 549 



and imbedded masses and veins, in porphyry, and in Oryctogno- 

 various secondary trap rocks. . _,-**' _. 



Geographic Situation. It. occurs in various parts of 

 Europe, Asia, Africa, and America. 



Uses. It is cut into ornamental articles of different 

 kinds. 



Second Kind __ TRANSPARENT OBSIDIAN, Jamaon. Transpa- 

 Durchsichtiger Obsidian, Hoffmann. 



External Characters. Colours blue, brown, and" 

 white. Internally splendent and vitreous. Fracture 

 conchoidal. . Perfectly transparent 



Geognostic and Geographic Situations. It occurs im- 

 bedded in pearlstone-porphyry, at Marekan in Siberia. 



SIXTH SUBSPECIES. 



PITCHSTONE, Jameson. Pechstein, Werner. 



External Characters. Colours green, grey, blue, yel- 

 low, brown, and black. Occurs massive. Internally 

 shining, and glistening ; lustre vitreo-resinous. Feebly 

 translucent on the edges. Fracture conchoidal, coarse. 

 grained uneven, and coarse splintery. 



Constit. Parti _ Silica, 73; Alumina, 14.50 ;Lme, 

 1.0; Oxide of iron, 1.00; Oxide of manganese, 0.10; 

 Natron, 1.75; Water, 8 50 = 99.85, Klaproth. 



Geognostic and Geographic Situations It occurs in 

 primitive, transition, and secondary rocks, in Scotland, 

 Ireland, Saxony, &c. 



Sf.vrsTii SUBSPECIES. 



PEARL-STONE, Jameson. Perlgtein, Werner. Pearl- 



External Character* Colours grey, black, and red. "one. 

 Occurs massive, disseminated ; also in roundish granu- 

 lar and curved lamellar concretions. Lustre shining 

 and pearly. Translucent on the edges, or translucent. 

 Very easily frangible. 



Constit. Paris. Silica, .77; Alumina, 13.0; Oxide 

 of iron and manganese, 2.0 ; Potash, 2.0 ; Lime, 1.5 ; 

 Natron, 0.7 ; Water, * = 100.2, Vauqudin. 



Geognostic ami Geographic Situation*. It occurs in 



Qhyry, in Hungary, Spain, north of Ireland, Ice- 

 , and Mexico. 



EIGHTH SI-BSFECIES. 



PUMICE, Jameson. Bimstein, Werner. 



External Characters __ Colours white and grey. Oc- 

 curs vesicular; vesicles much elongated, and contain 

 capillary fibres. Internally glistening or glimmering, 

 and pearly. Principal fracture curved and parallel 

 fibrous : cross fracture uneven. More or less translu- 

 cent on the edges. Very brittle, and easily frangible. 



Constit. Parts. Silica, 77-50; Alumina, 17.50; 

 Natron and Potash, 3.00 ; Iron with Manganese, 1.75, 

 = fi'i.75, Klaprolh. 



lirognoitic and Geographic Situations. Occurs along 

 with various porphyries and obsidians, in the Lipar! 

 islands, and other quarters. 



l.'set. Is used for polishing glass and soft stones ; 

 also by parchment- makers, curriers, and hat-makers, 

 and hence forms a considerable article of trade, and is 

 exported from the Lipari islands in great quantities to 

 the different countries of Europe. 



Observations. Obsidian, pitchstone, pearl-stone, and 

 pumice, ought to form a separate group in the species 

 of the Genus Quartz. 



GENUS VIII. AXINITE, Jameson. 



Prismatic. Perfect vitreous lustre. Hardness = 6.5 

 7.0. Specific gravity = 3.0 3.3. 



1. PRISMATIC AXINITE, Jameson. Prismatischer 

 Axinit, Mohs. Thutnerstein, Werner. 



Pyramid unknown. Cleavage prismatic = 101, SO'. 



External Characters. Colours clove-brown, plumb- 

 blue, grey, and black. Seldom massive, most frequent. 



Pumice. 



AxIXITF. 



axinite. 



