MINERALOGY. 



(fee Gypsum) contains 22 per cent, of water, and fome 

 varieties %% per cent. There are five varieties of anhydrite : 

 compaH,Jihrous, rad'mted, fparry, a.\idifcaly. 



Compact Anhydrite. — Its colours are various fhades of 



white, incHning to fmall bhie, blueidi-grey, and is alfo red 



and browniih-red. It occurs maflive, contorted, and reni- 



form. The contorted variety, from its refemblances to 



the convokitions of the inteftines, was called tripe-llone, or 



pierre de tripes. Compaft anhydrite is more or lefs tranflu- 



cent, is feebly glimmering, has a fmall fplintery frafture, 



pafling into even or conchoidal. The fragments are fharp- 



edged : it is difficultly frangible. Specific gravity from 2.8 



to 2.9. According to Klaproth, the conftituent parts are. 



Lime - - - - ■ 41.48 



Sulphuric acid - - 56.28 



Water - - - - .yy 



98.51 



Fibrous Anhydrites of a red colour : it occurs maffive, and 

 has a delicately fine and parallel fibrous ftrufture. Radi- 

 ated anhydrite has a blue or greyilli colour, and is fometinies 

 Ipotted v/ith red : it occurs malFive. The llruclure is radi- 

 ated, the furface fplendent and pearly : it is tranllucent and 

 rather hard. Its fpecific gravity and conftituent parts are the 

 fame as the former variety. 



Sparry Anhydrite, or Cube-Spar ; Chauxfidphalee laminaire, 

 Haliy. — The prevailing colour is white, inclining to blue- 

 grey, pale yellow, and red. It is more or lefs tranfparent, 

 the luftre iplendent and pearly : it refradfs doubly. It 

 is cryftallized in reftangular four-fided prifms, and in 

 fix or eight fided prifms. It alfo occurs maffive. It 

 has a foliated ftruclure, with a cleavage parallel with the 

 fides of a rectangular prifm, which is its primitive form. It 

 fcratches calcareous fpar, but is eafily frangible. The fpe- 

 cific gravity is 2.9. Before the blow-pipe, it becomes glazed 

 over with a white friable enamel, but does not melt and 

 exfoliate like gypfum. It is met with in the fait -mines in 

 the Tyrol, and in Switzerland, and alfo in the gypfum of 

 Nottinghamfhire. Scaly anhydrite is generally white, inclin- 

 ing to blue or grey : it occurs maffive, has a confufed foliated 

 ItruClure, and a fplendent and pearly luftre. It is tranflucent 

 on the edges, is eafily frangible, and is foft. Specific gravity 

 2.9. According to Klaproth, the conftituent parts are. 

 Lime - . . . 41 '75 



Sulphuric acid - - 5^. 



Muriate of foda - - i. 



91^15 

 It occurs in the fait -mines of Hall in the Tyrol. 



AxTHOPllYLlTE. Its colour is between dark yellowifh- 

 grey and olive-brown : it occurs maffive and cryltallized in 

 reed-ftiaped cryftals, which appear to be four-fided prifms 

 longitudinally ftreaked. Tiie luftre is iliining and pearly, 

 approaching to metallic. The ftrudture is radiated. It has 

 a two-fold cleavage parallel with the fides of a reftangular 

 prifm. It is more or lefs tranflucent, yields to the knife, but 

 fcratches glafs with difficulty. It is infufible before the 

 blow-pipe. Its fpecific gravity is 3.2. The conftituent 

 parts are, 



Silex .... 56.00 



Alumine ... 13.30 



Magnefia ... 14.00 



Lime .... 3.33 



Oxyd of manganefe - 3. 



Iron .... 6. 



Water - - - - 1.43 



This mineral is allied to hornblende : it occurs at Konio-/bercr 

 \n Norway. " ° 



AxTnuAciTE.or Anthracolite, flaty glance-coal and colum- 

 nar glance-coal. Anthracite is that fpecies of coal which 

 has .-1 ffimnig luftre approaching to metallic, and burns with- 

 out fmoke. Kilkenny coal and IVelJh culm are varieties of 

 anthracite. See Coal. 



Antimony, Native, and Ores of. See AxTlMOXY-Orw 

 and Red Antimony, Addenda. ' 



Apatite. (See Apatit.) Chaux phofphatee, Haiiy. 

 Werner makes two fub-fpecies of apatite, the common 

 and conchoidal. The latter, or conchoidal apatite, has a 

 conchoidal frafture : it has been called afparagus Jlone. 

 Apatite has been difcovered in Cornwall, and recently near 

 Bovey in Devonfliire. Maffive apatite and earthy apa- 

 tite have received from Werner the names of common 

 phofphorite and earthy phofphorite. Phofphorite has nearly 

 the fame conftituent parts as apatite, with an addition of 

 a fmall portion of fluoric acid, about 2-10 per cent. 



Aphrite. (See ScHAUM-£a;V/?i.) Aphrite is divided 

 mtofcaly aphrite, Jlaty aphrite. ^wA f parry aphrite. 



Aplome, a mineral clofel)- allied to garnet, but is fuD- 

 pofed to have a diff'erent primitive form of the cryftal or 

 that of a cube. (See Garnet.) Aplome is confidered by 

 Jamefon as cryftallized common garnet. 



ApoPHYLiTE. See Zeolite. 



Aqua, Marine. See Beryl. 



Akendalite. See Epidote, Addenda. 



Ahktizite, a name given by Werner to the mineral 

 iince called Wernerite. See Werxerite. 



Arragonite. (See Arragonite.) Since that article 

 was written, the remarkable anomaly in the cryftallization of 

 this mineral has been partly explained by the difcovery 

 that it contains a portion of the carbonate of ftrontian, which 

 is fuppofed to give a different form to its primitive cryltal. 

 The conftituent parts, as given by Stromeyer, are, 



Arragonite from Molina, in Arragon. 



Carbonate of lime - - 94-57 



Carbonate of ftrontian . 3-96 



Hydrate of iron . - .70 



Water .... .jq 



97.06 



Vol. XXXIX. 



Werner divides arragonite into common, columnar, and 

 acicular. Arragonite occurs in trap rocks in various parts 

 of Scotland, and we have acicular cryftals of an-agonite 

 in lava from Vefuvius. 



Arseniate o/Co/^fr. See Copper-Ores. 



Arseniate o/'/ron. See Iron-Ore, feftion Cube-Ore. 



Arseniate of Lead. See Lead, Ores of. 



Arsenic, Native. See Arsenic, Ores of. 



Arsenic Bloom. See Piiarmacolite, Addenda. 



Arsenic Oxyd, and Arfenical Pyrites, or Marcafite. See 

 Arsenic, Ores of. 



Asbestus, Common and Flexible, (fee AmianthuS and 



AsBESTUS, ) AJbeflus ligniform,QX wood afbeftus. Its colour is 



4 A wood- 



