MINERALOGY. 



521 



Oryctogne- smooth and shining. Internally dull, and, when glim- 

 7- mering, owing to its being intermixed with foreign 

 > '"V"'' parts. Fracture coarse splintery, passing into coarse 

 and fine grained uneven. Internally dull, seldom fee- 

 bly glimmering. Fragments indeterminate angular, 

 and blunt-edged. Translucent on the edges. Becomes 

 shining in the streak. Writes but feebly. Very sectile. 

 Rather difficultly frangible. Does not adhere to the 

 tongue. Feels very greasy. 



Chemical Characters Before the blowpipe, it loses 

 its colour, but is infusible without addition. 



Steatite of Monte Kamuzo. 



Fig-ure- 

 tone. 



Caiulituenl Parti. Silica . 44.00 



Magnesia, . 44.00 

 Alumina, . 2.00 

 Iron, . 7.30 



Manganese, . 1.50 

 Chrome, . 5.00 

 Trace of lime and 



muriatic acid. 100.80 



f'auquelin. 



Geognotiic Situation. It occurs frequently in small 

 cote mporaneous veins, that traverse serpentine in all di- 

 rections; and in angular and other shaped pieces in 

 secondary or floetz-trap rocks. It also occurs in metal- 

 liferous veins that traverse primitive rocks. 



Geographic Situation. It occurs in the serpentine of 

 Port soy and Shetland ; in the limestone of Icolmkill ; 

 and in the trap-rocks of Fifeshire, the Lothians, Ar- 

 ran, Skye, Canna, and other parts in Scotland. In 

 England, in the serpentine of Cornwall, and at Amlwch 

 in Anglesey. 



Ufa. The steatite of Cornwall is used at Worcester, 

 in the manufacture of porcelain. Like fullers earth and 

 indurated talc, it readily absorbs oily and greasy mat- 

 ter, and hence it is used for extracting spot* of grease 

 from silk and woollen stuffs. It is also employed in 

 polishing gypsum, serpentine, and marble. When 

 pounded and slightly burnt, it forms the basis of certain 

 cosmetics. It writes readily on glass, in which charac- 

 ter it differs from common chalk, which leaves no 

 trace ; hence it is used by glaziers, in marking plates 

 of glass before they are cut with diamond. 



TENTH SUBSPECIES. 



FIGURES-TONE, or AOALMATOLITE t, Jameton. B'M- 

 stcin, Werner. Agalmatolith, Klaprolh. 



External Character!. Colours grey, green, white, 

 red, and brown. Occurs massive. Internally dull or 

 feebly glimmering. Fracture large and flat conchoidal 

 in the large, splintery in the small, and sometimes im- 

 perfect slaty. Fragments indeterminate angular, ra- 

 ther sharp-edged, or imperfect tabular. Translucent, 

 sometimes only on the edges. Becomes feebly resinous 

 in the streak. Intermediate between sectile and brittle. 

 Feels rather greasy. 



Chemical Characters. \t is infusible before the blow, 

 pipe. Chinese Figurcftone. 



Geographic Situation. It occurs in China and at .Oryttojno- 

 Nagyag in Transylvania, but the geognostic situations >y- 

 are unknown. S ~""Y~^'' 



Uses. This mineral, owing to its softness, can easily 

 be fashioned into various shapes with the knife : hence, 

 in China, where it frequently occurs, it is cut into 

 human figures, also into pagodas, cups, snutf. boxes, 

 &c. 



CLAY-SLATE J, Jameson. Thonschiefer, Werner. 

 External Characters. Colours yellowish, ash, smoke Clay.sUte. 

 bluish, pearl, and greenish-grey ; from greenish-grey 

 it passes into a colour intermediate between leek-green 

 and blackish-green ; from dark smoke-grey into grey- 

 ish-black and bluish-black ; and from pearl-grey into 

 brownish-red and cherry red. Sometimes spotted, 

 striped, or flamed. Occurs massive. Lustre pearly, 

 glistening, or glimmering. Fracture more or less per. 

 feet slaty ; some varieties approach to foliated, others 

 to compact. The slaty is either straight, or undulating 

 curved, and the latter has a twofold obliquely intersect- 

 ing cleavage. Fragments generally tabular, seldom long 

 splintery or trapezoidal. Is opaque. A ffbrds a greyish- 

 white dull streak. Sectile, ami easily split. Feels ra- 

 ther greasy. Specific gravity, 2.661, Kirtvan. 2.706, 

 Kursti'n. 



Chemical Characters. It is fusible into a slag before 

 the blowpipe. 



Constituent Parts. Silica, . . 48.6 

 Alumina, . . 23.5 

 Magnesia, . 1.6 



Peroxide of Iron, 11.3 

 Oxide of Manganese, 0.5 

 Potash, . . 4.7 

 Carbon, . . 0.3 

 Sulphur, . . 0.1 

 Water, and Volatile 



Matter, . . 7.6 

 IA>, . . 1.8100 



Daubuisson. 



Geognoslic Situation. It occurs in primitive and trail, 

 sition mountains. 



Geographic Situation. It is a very generally distri- 

 buted rock throughout the mountainous regions in the 

 different quarters of the globe. It abounds in many of 

 the Highland districts in Great Britain and Ireland, 

 and in several of the smaller islands that lie near their 



w 



Uta. It is principally used for roofing houses. 

 WHET-SLATE, Jameson. Wetzschiefer, Werner. 



Contl. Parti. Silica, 



Alumina, 

 Lime, 

 Potash, 

 Iron, 

 Water, 



35.00 

 29.00 



2.00 



7.00 



1.00 



5.00 99-00 I'autjuelin. 



External Characters Most common colour green- late. 

 ish-grey ; it is found also mountain, asparagus, olive 

 and oil green. Occurs massive. Internally feebly 

 glimmering. Fracture in the large is straight slaty ; in 

 the small, splintery. Fragments tabular. Translucent 

 on the edges. Streak greyish- white. Soft in a low de- 

 gree. Feeb rather greasy. Specific gravity 2.782, 

 Kartsen. 



Geognostic Situation. It occurs in beds in primitive 

 and transition clay-slate. 



Geographic Situation. Very fine varieties are brought 

 from Turkey. 



f J/folmatoKte, turn the Greek word* .J-.XMJ. and Xj9, which upiifiei Jlgurc-tttme, became it u cut into figures of different kind* in 

 Ac coontric* where it i* principally found. 



J Clay-tlate, whet-date, black chalk, and alum-ilate, an placed immediately after the lubipeciet of fihomboidal Mica, on aoount of 

 tfieir affinity with it. 



I HOUKI roofed with the red Tarierr of cUy-tlatt, appeal u if eorend with copper. 



VOL. XIV. PART II. 3 u 



