ME R

( 71 ) MER

filver. Hence it never occurs in the mines ofIdria or Almaden , but is far from rare in thofeof Roienau, in Upper Hungary ; it is alfo metwith at Sahlberg in Sweden, Morsfeld , in thePalatinate , and Mofchellandfberg, in DeuxFonts.

It is ufually found in red and grey induratedclay, accompanied by native mercury, fpathofeiron ore, grey antimony, and grey copper.

Sp. 3. Liver-coloured mercurial ore. Qtieck-jtlber leber-erz, Wern. Mercure hepatique, Broch.Of this fpecies there are the two followingvarieties.

1 Var. Compact.

The colour is intermediate between darkcochineal red and lead-grey. It occurs maffive.Internally it has a gliftening femi-metallic luftre.Its fracture is even, palling into fine graineduneven, or imperfectly flat conchoidal. Itsfragments are indeterminately angular, fome-what blunt edged. It is opake; receives apolifti. by friCHon, and gives a ftreak of a co-chineal red colour. It is foft, may be cut by aknife, and is eafily frangible, fp.gr. 7.18 to 7.93.

2 Var. Slaty.

Its colour is the fame as the preceding, onlya little more red. It occurs in mafs. Its lon-gitudinal fracture is Alining with a metallic,luftre ; its crofs fradture is only glimmering..Its longitudinal fracture is thick and curvedflaty; its crofs fracture is compact and even.Its fragments are flaty •, it is opake, and veryeafily frangible.

Both thefe varieties are mixed with cinnabar,native mercury, iron pyrites and clay. Theproduce of mercury varies from, lefs than 20 tomore than 70 per cent; the compact is ufuallythe richeft, containing a lefs proportion ofearthy matter than the other. It has not beenanalyfed with much accuracy, but it appearsthat at leaf! a confiderable portion of its mer-cury is in the Rate of fimpleired oxyd.

It occurs in abundance at Frioul in Iftria,Almaden in Spain , in the Duchy of Deux Fonts,and Nertfchinfk in Siberia .

Sp. 4. Bituminous mercurial ore.

Of this there are the two following varieties.

r. Var. Branderz.

This is a kind of coarfe coal of a reddifh-black colour. It occurs in mafs, or in balls dif-feminated through bituminous fhale. Whenheated it takes fire, and burns with a whiteflame.

2. Var. Corallenerz.

This is the bituminous fhale in which the'balls of the preceding variety are implanted,.

and, like that, it burns when heated, with awhite flame.

The bituminous mercurial ore occurs at Idriain Carniola, and Nertfchinik in Siberia , in con-fiderable abundance: it contains from 2 to 20per cent, of mercury. It has not been analyfed,but it is certain that part of the mercury that itcontains is in the native ftate, the reft is fuppo—fed for the moft part to be in the ftate of muriat.

Sp. 5. Cinnabar. Zinnober , Wern. Cin-nabre , Broch.

Of this there are the three following fub-fpecies.

1. Sub/p. Common, or dark red, C. Dun -»•kel rather, Z. Wern.

Its colour is cochineal-red, which in fomevarieties pafles to carmine-red, and in others to-lead-grey. It occurs in mafs, difieminated, in-verting, cellular, dendritic or cryltallized. Theprimitive form of its cryftals is the regular hex—ahedral prifm, befides which the following,varieties occur.

x. The fame with three alternate terminal,edges of the prifm deeply bevilled.

2. A tetrahedral pyramid.

3. An octohedron, compofed of two tetrahe-dral pyramids.

4. A Angle trihedral pyramid.

5. A double trihedral pyramid, either with,or without an intervening trihedral prifm.

6. The fame as var. 1. curved into a lenti-cular form by the addition of feveral irregulartruncatures.

The cryftals are fmall, and very fmall, and,ufually occur in clufters. The cryftals arefplendent externally and internally, are more orlefs fhinmg with almoft a femi-metallic luftre.Its fracture is fine-grained uneven, fometimes-even and' conchoidal; alfo as it approaches tothe cryftalline ftate, more or lefs perfe&ly foli-ated. Its fragments are indeterminate andblunt-edged.. The foliated varieties prefentfine-grained diftindt concretions. The mafiive.cinnabar is opake, or at moft tranflucent on theedges ; the cryftallized is tranflucent, and femi—tranfparent. It acquires a luftre by fridtion,and'when pulverized is of a fcarlet-red colour.It is foft, may be cut with a knife, and is eafily.frangible. Sp. gr. of the compact, when mode-rately pure, 7.2 to 7.3; of the cryftallized, 10.12.Its conftituent parts according to Lampadiusare 81. Mercury

15.2 Sulphur4.7 Iron

100.9..