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It occurs in veins of quartz, calcareous fpar,and heavy fpar, accompanied by native fnverand other ores of the lame metal, alfo by ironochre, galena, malachite, grey copper, andcobalt ochre.
It is fometimes invifibly difperfed through.compact limeltone, forming the alkaline ore ofJufti, and which contains about 2 oz. of'muriated filver in the quintal.
Hornfilver occurs in confiderable abundance'in the Mexican and Peruvian mines: the Saxonand Bohemian mines, efpecially thofe of Johann-georgenftadt, ufed to afford great quantities ofit, and it is ftiil found there, though by nomeans fo plentifully as formerly. It is alfo metwith at Schemnitz in Hungary , Chaianchesnear Allemontin France, and rarely in CornwalL
2 Subfp. Earthy Hornlilver. Butlermilcherz ,Germ.
Its colour is greenifh-white, date blue, orreddifh brown. It occurs in thin fuperficialcrufts, or diffeminated. It is without luttre.Its fracture is fine grained, earthy. It is veryfoft, almolt friable; is brittle; acquires a flight'greafy lultre by friction; it is fomewhat unc-tuous to the touch.
When expofed to the blowpipe it {lightlyagglutinates, and minute globules of filver maketheir appearance. It confifts, according toKlaproth , of
24.64 Silver8.28 Muriatic acid
67.08 Alumine with a trace of copper100.
It occurs at Andreafberg in the Hartz.
Sp. 6. Red Silver ore. Ruby Silver.Rothgultigerz , Wern. Argent rouge, Broch.
Its colour is carmine red, light blood red,cochineal red, paffing into lead-grey, and ironblack. It occurs in mafs, diffeminated, inkidney-fliaped pieces, in membranes and cryf-tallized. Its primitive cryftalline form is anobtufe rhomboid, the plane angles of whichjneafure 104 0 28' and 75 0 32': it alfo prefents
1. The llraight fix-fided prifm.
2. A fix-fided prifm, truncated by trihedralfummits with rhomboidal faces.
3. The fame as the preceding with thelateral edges of the fummits truncated.
4. 1 he fame as var. 2 with the point ofthe fummit replaced by a triangular plane.
5. The fame as var. 2 with all the edgestruncated.
6. A dodecahedron compofed of two fix-
fided pyramids, with fcalene triangular facesjoined bale to bafe.
7. The preceding, with the pyramids ("greatlylengthened) truncated and terminated by fix-fided pyramids with triangular faces, or trihe-dral pyramids with rhomboidal faces.
8. Acicular prifms.
The cryflals are fmall and very fmall, andoften occur in drufes. Externally they aremore or lefs brightly fhining with a lultre be-tween that of the diamond, and femi-metalUc.Internally this mineral is finning or glimmeringwith a femi-metallic lultre. Its frafture islarge or fmall-grained uneven, alfo imperfectlyand fmall conchoidal and rarely imperfedtly la-mellar. The fmall light coloured cryflals areoften tranfparent, other varieties are tranflucentand even opake. When fcraped it affords apowder of a bright orange-red paffing into dullerimfon. It is foft, moderately brittle andeafiiy frangible. Sp. gr. about 5.6.'
When expofed to the blow-pipe it cracklesand flies before it becomes red-hot; it thenmelts with a flight effervefeence emitting a yel-low vapour, and at length yielding a globuleof filver.
The light coloured variety has been analyfedby Klaproth and Vauquelin, with the followingrefults,
Klapr. Vauq.
56.67 Silver
16.13 Antimony15.07 Sulphur
o. Sulphuric acid
12.13 Oxygen
100. 100. — 100.
It occurs in veins with quartz, calcareousfpar, brown fpar, native arfenic, iron pyrites,galena, blende, various filver ores, and occafi-onally native gold. It is met with at Kremnitz and Felfobanya in Hungary, Freyberg in Sax-ony , Andreusberg in the Hartz, Joachimflhalin Bohemia, Guadalcanal in Opain, and St.Marie aux Mines in France .
Sp. 7. Sulphurated filver ore. Silberglaferz, Wern. Glanzerz. Lens. Argent vi-treux. Broch.
Its colour is deep lead-grey, paffing intogreyiffi black; on the furface it is often moreor lefs iridefcent. It occurs in mafs, diffemin-ated, membranous, capillary, dendritic, cor-roded or cryftallized.
1. In double four-fided pyramids, not un-
20.3 - 18.5