524 



MINERALOGY. 



Oryctogno- 



Precious 

 Serpentine. 



Splintery 

 Precious 

 Serpentine 



Geognof tic Situation. Serpentine occurs in primi- 

 tive, transition, and secondary rocks. 



Geographic Situation. In Scotland, it occurs in the 

 islands of Unst and Fetlar, in Shetland ; Isle of Glass 

 in the Hebrides ; at Portsoy in Banftshire ; near Drim- 

 nadrochit, and the town of Inverness, in Inverness- 

 shire ; at the Bridge of Cortachie in Forfarshire ; and 

 between Ballantrae and Girvan, in Ayrshire. It a- 

 bounds in some districts in Cornwall in England ; and 

 it occurs at Cloghan Lee, on the west coast cf Ireland, 

 in the county of Donnegal. 



Uses. As it is soft and sectile, and takes a good 



polish, it is cut and turned into vessels and ornaments 

 of various kind. 



b. PRECIOUS SERPENTINE, Jameson. Edler Serpentin, 

 Werner. 



This mineral is divided into two sub-kinds, viz. 

 Splintery Precious Serpentine, and Conchoidal Precious 

 Serpentine. 



a. SPLINTERY PRECIOUS SERPENTINE, Jameson. Edler 

 Splittriger Serpentin, Werner. 



External Characters. Colour dark leek-green. Oc- 

 curs massive. Internally it is feebly glimmering. 

 Fracture coarse and long splintery, and sometimes in- 

 clines to slaty in the large. Fragments rather sharp- 

 edged. Feebly translucent. Soft, passing into semi- 

 hard. Specific gravity, 2.704, Breilhaupt. In other 

 characters it agrees with Common Serpentine. 



Gecgnoslic and Geographic Situations. It occurs in 

 the Isfand of Corsica, and in Bareuth. 



Use. In Corsica it is cut into snuff-boxes, and other 



similar articles. 



Conchoidal 



Precious 



Serpentine. 



(3. CONCHOIDAL PRECIOUS SERPENTINE, Jameson. 

 Edler muschlicher Serpentin, Werner. 



External Characters. Colour leek-green, whichsome- 

 times passes into blackish-green ; seldom into Pistachio- 

 green, siskin-green, and oil green. Occurs massive, 

 and disseminated. Lustre glistening, passing into 

 glimmering, and is resinous. Fracture flat Conchoidal. 

 Fragments sharp-edged. Translucent, but only trans- 

 1 ucent on the edges in the dark varieties. Intermediate 

 between soft and semi-hard. Specific gravity 2.561, 

 2643, Breithaupt. In other characters it agrees with the 

 foregoing. 



Constituent Parts. Silica 



Magnesia 



Lime 



Alumina 



Oxide of iron 



Oxide of Manganese 



Oxide of Chrone 



Water 



6. FULLERS EARTH, Jameson. Walkerde, Werner. Oryctogno. 

 External Characters. Colours white, grey, and green. .._,-**',_,. 

 Some varieties exhibit clouded and striped coloured de- p^., 

 lineations. Occursmassive. Dull. Fracture coarseandfine Earth, 

 grained uneven; some varieties are large conchoidal; and 

 others incline to slaty. Fragments blunt-edged, and 

 occasionally incline to slaty. Opaque ; but when it 

 inclines to steatite it is translucent on the edges. Be- 

 comes shining and resinous in the streak. Very soft, 

 sometimes nearly friable. Sectile. Scarcely adheres 

 to the tongue. Feels greasy. Specific gravity, 1.72, 

 Karslen. 1.198, Hoffmann. 2.198, Breithaupt. 



Chemical Characters. It falls into powder in water, 

 without the crackling noise which accompanies the dis- 

 integration of bole. It melts into a brown spongy sco- 

 ria before the blow-pipe. 



Fullers earth of Ryegate. 



Constituent Parts. Silica . 53.00 



Alumina 10.00 



Magnesia . 1.25 

 Lime . 0.50 



Muriate of Soda 0.10 

 Trace of Potash. 

 Oxide of Iron 9-75 

 Water . 24.00 98.60 

 Klaproth, Beit. b. iv. s. 338. 



Geognostic and Geographic Situations. In England 

 it occurs in beds sometimes below, sometimes above the 

 chalk formation ; at Rosswein, in Upper Saxony, under 

 strata of greenstone-slate ; and in different places in 

 Austria, Bavaria, and Moravia, it is found immediately 

 under the soil. 



Uses. This mineral was employed by the ancients 

 for cleaning woollen, and also linen cloth, and they 

 named it Terra Fullonum, and Creia Fullonum ; hence 

 the name Fuller's Earth. The Morochtus of Dioscorides, 

 which he celebrates on account of its remarkable sapo- 

 naceous properties, is conjectured to have been a varie- 

 ty of fuller's earth. 



GENUS. VIII. PEARL MICA. PlABL 



One axis. Cleavage rhomboidal. Streak white. Hard- *i. 

 ness=3.5. Sp. gravity=3.0. 3.1. 

 I. RHOMBOIDAL. 



Rhomboid unknown. Cleavage parallel with the 

 terminal planes of the regular six-sided prism. 



OKDEE VI. SPAR. OrdsrVl. 



No metallic lustre. No adamanine lustre. Streak SpAR - 

 , white. Hardness ranges from 3.5 to 7-0; if above 6, 

 ' 50 there are single distinct cleavages. Specific gravity 

 'fiv ranges from 2.0 to 3.7 ; if 2.4 and less, it is not amor- 



42.50 



38.63 



0.25 



1.00 



1 



0.62 



0.25 



15.20 



ranges 

 phous *. 



GENUS IX. SCHILLER-SPAR. 



Schiller Spath, Mohs. 



Three axes. Cleavage prismatic. Pearly lustre on 



John, Chem. Untersuchungen, 



b. ii. s. 218. 



Geognostic Situation. It generally occurs intermixed .* c i eav ag es . If common pearly lustre, "the specific 



with foliated granular limestone in beds subordinate ity _ 3 2an d less, the hardness=5.5 and less, and 



to gneiss, mica-slate, and other primitive rocks. It some- olou / n . Hardness ranges from 4 to 6. Sp. gra- 



times occurs in cotemporaneous masses m common s fr ^ 3 to 3 4 



pentine, and then it occasionally contains scales of mica. / ^ COIltains four spec ies, viz. 1 . Prismatic, or 



Geographic Situation It occurs at Portsoy in *>a.ntt- G Disllage 2 Slaty or Common Schiller-spar, 3. 



lire, and in the Shetland islands ; m the island < brador O r Hyperstene, 4. Straight, or Anthophylite. 



SCHILLER 



6PAU. 



shire, 

 Holyhead, 



Utes. It receives a finer polish than common ser- 

 pentine, and was much used by the ancients for pillars 

 an,d other similar ornamental purposes. At present it 

 is also in great esteem as an ornamental stone. 



1 PRISMATIC SCHILLER-SPAR, or GREEN DIALLAGE, I'rtanaife 

 Jameson. Prismatische Schiller Spath, MoAs.Diallage 

 Verte, Hauu. KornigerStrahlstein, Werner. 



Prism unknown. Cleavage prismatoidal. Common 



' The cleayag, not given, therefore the character! of ibis oidei are incomplete. 



