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either fmooth or drufy, and therefore theirexternal luftre is fubject to correfponding varia-tions. The fracture is fdr the moft part di-vergingly radiated in ftars or bundles, with fhort(trait fibres. It fometimes paffes into parallel-fibrous, and even into compact. Its fragmentsare wedge-fliaped. It occurs in coarfe andlarge granular diftindt concretions, alfo in thincurved lamellar, and in thin columnar diftindtconcretions. It is hard, brittle, and very eafilyfrangible. Sp. gr. 4.69 to 4.77.

It is compofed according to Hatchett ofSulphur 53.6 — 54.34

Iron - 46.4 — 45.66

100. 100.

It is rarer than common pyrites, and occursprincipally in final! malfes, and in veins withores of lead or filver. In Britain it occurs inCornwall , the Ifle of Sheppy, and Derbyflure.It is remarkably fubject to decompofition onexpofure to the air and moifture, and hence ismuch fought after by the manufacturers ofgreen vitriol.

3. Subf. Capillary pyrites. Haarkies. Wern.Pyrite Capiliaire. Broch.

Its colour is bronze yellow, palling into fteel-grey. It occurs in delicate capillary cryftalsaggregated into divergent bundles or promifcu-oufly. In other particulars it agrees with thepreceding, of which it is little elfe than avariety.

It is the lead frequently met with of any ofthe kinds of pyrites. It occurs in veins withlead and filver ores, accompanied by quartz,calcareous and fluor fpars, in Saxony and theHartz.

4. Subjp. Cellular pyrites. Zell-kies, Wern.

Its colour is bronze yellow inclining to green-

ilh and fteel-grey. It becomes of a grey colourby tarnifhing. It occurs cellular: its fradtureis even and flat conchoidal palling into fine-grained uneven. In other refpedts it refemblescommon pyrites, into which it occafionallypaffes. It is the leaft fubjedt to decompofitionof the whole fpecies. It occurs in metallicveins in Saxony.

5. Subfp. Liver pyrites. Leberkies , Wern.Pyrite hepatique> Broch.

Its colour is intermediate between pale brafs-yellow and fteel-grey; its external furface isufually brownilh or iridefcent. It occurs inmafs, difleminated, globular, tuberous, reniform,ftaladlitie and cellular; alfo cryftallized in fix-

fided prifms or pyramids. Internally it is ufuallyglimmering, with a metallic luftre. Its fradlureis even, palling into fine granular or flat con-choidal. It occurs in diftindt concretions. Itis met with only in metallic veins and is veryfubjedt to decompofition.

Sp. 3. Magnetical Pyrites. Magnetkies,Wern. Pyrite magnetique, Broch.

Its colour is intermediate between brafs-yel-low and copper-red, and fometimes inclines totombac brown : by expofure to the air it acquiresa brownilh tarnilh. It occurs only in mafs anddifleminated. Internally it is fhining or glif-tening, with a metallic luftre. Its fradlure isfine or coarfe grained uneven, fometimes pallinginto imperfedf conchoidal. It breaks into in-determinate blunt edged fragments. It affordsa few occafional fparks with fteel; is brittleand eafily frangible. Sp. gr. 4.518.

It is efpecially diftinguilhable from the pre-ceding fpecies in being attradled by the magnetand giving out fulphuretted hydrogen by digef-tion in muriatic acid. It* component parts,according to Mr. Hatchett, are

Sulphur - - 36.5

Iron - - - 63.5

100.

It is faid to be found only in beds in primitivemountains, in gneifs, micaceous fchiftus, primi-tive greenftone and limeftone, where it occurswith common martial pyrites, copper pyrites,,arfenical pyrites, galena, blende, magnetic iron-ftone, garnet, hornblende, and adlynolite. It ismet with in Bohemia, Bavaria , and Silefia, alfoin Norway , and has recently been found byMr. Greville near the bafe of Moel Elion inCaernarvonlhire, where it forms a thick vein ormore properly a bed, as Jamefon conjedtures.Befides the above localities it occurs difleminatedin tranfition greenftone a little to the fouth ofPont Aberglaflyn in Caernarvonlhire; andforming a large bed with black calcareous fparin tranfition Hate, not far from Trefriew in thevale of Conway, in the fame county. At thislaft place it is procured in confiderable quantityfor the fulphur which it yields by fublimationand the red ochre which remains after the repa-ration of the fulphur. ‘

Sp. 4. Magnetical Iron Stone.

Of this there are the two following fubfpecies.

1. Stibfp. Common Magnetic Iron (tone.Gemeiner Magneteifenjiein^ Wern. Fer magnetiquecommun , Broch.

* Own Obfervatious.