MINERALOGY. 



557 



ConilitMtnt Paris. 



79.0 

 1.00 

 1.00 

 4.00 



Silica, 

 Alumina, 

 Lime, 



Oxide of iron, 

 Water, 

 Bucko!:, in Joum. fur d- Chemie et Physik, b. ii s. 28, 



gnostic ami Geographic Siluatijus It forms a 

 bed in"the neighlxnirhood of rocks of the coal-forma- 

 tion, at Planitz in Saxony. 



1\. TRIPOLI, Jamrson. Tripel, Werner. 

 External Character'. Colours grey, white, and yel- 

 low. Occurs massive, and in whole beds. Dull. 

 Fracture sometimes fine, sometimes coarse earthy, ami 

 in the great inclines to slaty. Opaque. Soft, somc- 

 time* pacing inti) very sot't. Not very brittle, and 

 rather easily frangible. Feels meagre, and rather 

 rough. Does not adhere to the tongue. Specific gra- 



.202, Bucholz. 



Chemical Character. It is infusible before the blow, 

 pipe. llottenstone. 



Constituent ParU. Silica, . . 4 



Alumina, . 86 



Carbon, . . 19-100 

 Phillip. 



GeogtKttic Situation. It occurs in beds in co:il t 

 also iri beds, along with secondary limestone, and al- 

 ternating with clay, under basalt. 



pr/ji.fiit Xituali -n. It is found at Bnkewell in 

 Derbyshire, where it is named Rottenttont, and in many 

 other parts of the world. 



Ute*. On account of the hardness of its particles, 

 it is used for polishing stones, metals, and glasses. 

 * LITIIOMARGE FAMILY. 



I. LITIIOMAHOC, Jameson Steinmark, Werner, 

 'trnal Characters Colours white, grey, blue, and 



yellow. Occurs massive, disseminated, and globular 

 or amygdaloidal. Dull. Fracture fine e.irthy in the 

 small, and large conchoidal, and sometimes even, in 

 the great. !>.-.; nt* indeterminate angular, and 

 rather blunt-edged. Opaque. Becomes fliiun 

 tie streak. Very tol\, sect i If, and easily frangible. Ad- 

 heres strongly to the tongue. Feels line and greasy. Spe- 

 cific gravity,''2.41.'), Kopp 2,4.15 2.492, Brcithaupl. 



Geognoitic and Geographic Situations. It occurs in 

 veins in |>rphyry, gneiss, grrywackc, and serpentine: 

 in dnuy cavities in topaz-rock ; or nidtilar, in basalt, 

 amygdaloid, and serpentine ; and it is said al.--o in beds, 

 in a coal-formation. It is found in Scotland, England, 

 Germany, &c. 



II. MOUNTAIN SOAP, Jameson. Bergseif^ Werntr. 

 External Characters Colour pale brownish-black. 



Occurs massive. Dull. Fracture fine earthy. Frag- 

 ments indeterminate angular. Opaque. Becomes 

 shining in the streak. Writes, but does not soil. Very 

 soft, and perfectly sectile. Easily frangible. Adheres 

 strongly to the tongue. Feels very greasy. Liglit, 

 bordering on rather neavy. 



Geogvnslic and Geographic Siluatiuns. It occurs in 

 trap-rocks in th* island of Sky e. 



Use. It is valued by painters as a crayon. 



III. YeLLow EARTH, Jameson. Gelberde, Werner. 

 Argile ocreuse jaune grapl.iquo, Haiiy. 



is. -Colour ochre-yellow, of dif- 

 ferent degrees of in; ( >ccurs masiive. Dull on 

 mm fr.icture, but glimmering on the principal 

 fracture. Fracture in tlie large inclines to slaty ; in 

 earthy. Fragment* tabular, or indeter- 

 minate angular. Becomes somewhat shining in the 

 \M and writes fl;chtly. Very 

 ,'as--.in,f int.- friable. Easily tangible. Adheres 

 pretty strongly to the tongue. Feels rather gi. 

 Specific gravity, 2.240, Breilhaupl. 

 rou xir. PART 11. 



Gconosiic and Geographic Situations. It is found Orcytogno- 

 at We'iiraw, in Upj>er~Lusatia, where it is associated ^ _^ 

 with clay, and clay ironstone. "~Y~ 



I/JM. It may be employed as a yellow pigment ; 

 1400 9900 and when burnt, it is sold by the Dutch under the 

 name of English red The remains in Pompeii show 

 that it was used as a pigment, both in its yellow and 

 red state, by the ancient Romans. It appears to have 

 been known to Theophra-tu* as a yellow pigment. 



VI. BOLE*, Jameson. Bol, Werner. Bolf. 



Erterral Characters Colours brown, yellow, nnd 

 verv rarely pale flesh-red, and brownish-black. Some- 

 time* spotted and dendritic. Massive, and dissemi- 

 nated. Internally lustre glimmering, and very rarely 

 dull. Fracture perfect conchoidal. Red variety fee- 

 bly translucent, the yellow translucent on the edges, 

 and the brown and the black opaque. Very soft, ap- 

 proaching to soft. Rather sectile. and very easily 

 frangible. Feels greasy. Becomes shining and resin- 

 ous in the streak. Adheres to the tongue. Specific 



pravity. 1.<)>2. Kartten From 1.4 to 2.00, Kirnan. 



1.7 7 7,' 2.031, lirdtliaiqit. 



('.heiiical Character*. When immersed in water, it 

 breaks in pieces with an audible noise, with the evo- 

 lution of air-bubbles, and falls into powder. Before 

 the blowpipe, it melts into a gMnA&'grty coloured slag. 



Geognalic Situation. The geognostic situation ol' 

 t!ii* mineral is rather circumscribed, it having been 

 hitherto observed only in secondary or fla-tz trap-rocks, 

 ])rincipa)ly in trap-tuff, wacko, ai,d hn.vilt, in which it 

 occurs in angular pieces, and di-ieminated. 



Geographic Situation. It is found at Strigau in 

 Silesia, and in other place*. 



i'fet. It was formerly an article of the Materiu 



Medial, and used as an astringent, and in some places 

 i- *till employed in veterinary practice. It is s:iid that 

 tobacco-pipes rc sometimes made of bole, and that it i> 

 an ingredient in theglaz" of some kinds of earthen ware. 



GENUS VIII. AUGITE. AucrxE. 



Prismatic. Hardness = 4.. r >, 1. If above G, the ' 

 Sp. gr. = 3.2 and more. Sp. gr. = 2.7. 3.5. Be- 

 J is easily cleavablc according to an oblique prism. 

 No metallic pearly lustre. 



This genus contains four species, viz. 1. Oblique- 

 edged Augite. 2. Straight-edged Augite. 3. Prisma- 

 toidal Augite. 4. Prismatic augite. 



I. OsLiQUE-KOttEO AfoiTE, JametoH. Schiefkaiiti- oiiliquc- 

 ger Augit, Mo/is. c-Jgcd 



Prism = f2 18'. Cleavage indeterminate diagonal. Augiie. 

 Hardness = 5.0 G.O. Sp. gr. = 3.2 3.5. 



This species contains seven subspecies, viz. Foliated 

 Augite, Granular Augite, Conchoidal Augite, Coiiiinuii 

 Augite, Coccolite, Diopside, and Sahlite. 



FIRST SUBSPECIES. 



FOLIATED AUGITE, Jameton. Bhettrigcr Augit, KoliatvJ 

 Werner. 



EiternalCharacters. Colours black and green. Crys- 

 tallized in sivsided prismi, bevelled on the extremities, 

 and also in twin-crystals. Internally it is shining, inclin- 

 ing to splendent, and the lustre resino-vitreous. Frac- 

 ture conchuidal. Opaque, or translucent on the edges. 

 Chemical Characters. Fusible with difficulty into a 

 black enamel. j rom jEtat^ 



ComlUuenl Parts. Silica, . . 52.00 

 Alumina, . 5.33 



Mignesia, . . 10.00 

 Lime, . . 1S.20 

 Oxide of Iron, 14.66 



Oxideof Manganese, 2.009519. 

 ,'iclin, Journ. de Mm. N. 3p. p. 176. 

 GrogttOil., ,i. Occurs only in secondary trap- 



rock*, and in lava. 



SY 



