S TE
( 341 ) STR
33- Silex _
44. Alumine3.84 Lime13. Oxyd of iron
1. Oxyd of manganefc
94.84Lofs 5.16
ICO
It is found in St. Gothard in Switzerland ,fn fmall cryftals imbedded in micaceous fchiftus,and accompanied with cyanite ; in Brittany nearQuimper , in middling fized cryftals, imbeddedin a micaceous clay, apparently produced by thedecompofition of tome primitive rock: alfo atSant Jago of Gompoftella, in a primitive rock.
STAUROTIDE . See the preceding article.
STEATITE. Speckftein , Wern. Soapftone,Spanifh Chalk, Craie d'e Bviangon.
Its colour is grevifh, greenilh, yellowifh, orreddifh-white, alfo flefh-red, mountain-green,and olive-green : the whitifh varieties generallycontain black dendritical figures and fpots. Itoccurs in mafs, difleminated, invefting andcryftallized. The forms of its cryftals- are afix-fided prifm, terminated by fix-fided pyramids;alfo a reftangular and rhomboidal four-fidedprifm ; alfo a double fix-fided pyramid. It isprobable however that feveral if not all of thefeare pfeudomorphous. The cryftals are fmall andmiddlefrzcd, generally imbedded in the maflivekind, and are very rare. Internally it is dull;or at moft faintly glimmering. Its fradlure iscoarfe fplintery, rarely earthy, and fometimesintermediate between coarfe fibrous and foliated.It is tranflucent on the edges, rarely tranflucent.It is foft and very foft, gives a finning {freak,may be cut with a knife, is not very frangible,is very un&uous to the touch like foap. Sp.gr. 2.64. Before the blowpipe it becomes hardand generally lofes its colour, but is not fufiblewithout addition.
The fteatite of Bareuth, according to theanalyfes of Klaproth and Wiegleb, confifts ofthe following ingredients.
Klap, Weigh59-5 — 58-33 Silex3 0> 5 • 39- 1 <5 Magnefia
2 -5 2.5 Oxyd of iron
5.5 — o. Water
9 8 -° 99-89-
a_L-m ■
The fteatite of Cornwall , according to Klaptroth, confifts of
48 Silex
20.5 Magnefia
14. Alumine
1. Oxyd of iron
15.5 Water
99 -s
It occurs in beds and veins in ferpentine,alfo in nodules in various other rocks, particu-larly thofe of the Floetz-trap formation. It isfound in Cornwall at the Lizard Cape, imbeddedin ferpentine, alfo at Portfoy, in Scotland , inferpentine, and in the Ifle of Skye in wakke.It abounds in the principality of Bareuth, inSaxony, Bohemia, Norway, Sweden , andFrance .
The white varieties and thofe that become foby calcination, are employed in the manufac-ture of the fineft porcelain. Other varietiesare faid to be ufed for fulling.
STEEL . See Iron.-- STEEL ORE.
A common name for fpathofe iron ore: feeIron, p. 516.
STILL. An article of chemical apparatus,See the Appendix .
STINK,STEIN. See Swinstone.
STRAHLSTEIN. Actynelite, Kirw-. Ac-tinote, Hauy. Rayonnante , Broch.
Of this mineral there are the three followingfubfpecies;
1. Subfp. Common Strahlftein.
Its colour is olive or leek green, mountaingreen, blackifh green, reddifh, yellowifh, orgreenifh white, liver brown, and reddifh brown,'It occurs in mafs, difleminated or cryftallized.The primitive form of its cryftals is a veryoblique rhomboidal prifm, the alternate anglesof which are 124 0 and 56°. Sometimes theprifm is truncated on its acute lateral edges aswell as on its terminal angles and edges. It alfooccurs in {lender needle-fltnped cryftals. Thecryftals are ftriated longitudinally, and are verybrilliant externally, Internally this mineral fsmore orkfs {billing, with a vitreous luftre. Itsfradlure is broad radiated; either parallel, di-verging, bundled, or in Itars, very rarely la-mellar. Its fragments are fometimes wedgefhaped, but more commonly indeterminate,blunt edged. It occurs in wedge fhaped pril-matic, and in granular diftinci concretions.The cryftals are tranflucent, and even femi-