Thirty-third Species. Cross-stone,

The colour is a greyish-white. It occurs crystalized, either in broad rectangular four-sided prisms, or in win crystals. The crystals are mostly small, and aggregated on one another. Both the internal and the external lustre is shining, inclining to splendent or glistening.

The cross-stone is translucent passing to transparent, semi-hard, easily frangible, and not particularly heavy. It has hitherto been found only in mineral veins, and in agate-balls at Strontian, in Argyleshire, and at Andreasberg, in Hartz, as well ⚫ as some other places.

Thirty-fourth Species. Agate-stone.

The colour is a perfect azure blue, of different shades. It is found massive, disseminated, and in rolled pieces. The lustre is glistening and glimmering. It is translucent on the edges, pretty hard, brittle, easily frangible, and not particularly heavy.

The geognostic situation is not correctly ascertained. It is said to have been found near the lake of Baikal, in Siberia, in a vein accompanied with garnet, felspar, and pyrites. It occurs in Persia, China, Tartary, and Siberia; in South America; but in Europe has only been found among the ruins

of Rome.

Its beautiful colour renders it an object of attraction, and being capable of receiving a high polish, it is applied to various useful purposes, and enters into the composition of many different ornaments. It is the lapis lazuli of painters. Werner is constantly making additions to his species under every genus.

Of those belonging to the flint genus, which are less known, and have been described with less precision than the preceding, are coccolite, found in Sweden and Norway; pistazite, found in Norway, Bavaria, and France; ceylanite, in Ceylon; enclase, in Peru; hyalite, near Frankfort; menilite, near Paris; lomonite, in Lower Britanny; natrolite, in Suabia; azurite, in Stiria, &c.; andalusite, or hardspar, in Saxony, France, and Spain; chiastolite, or hollow spar, in France and Spain, and probably in Cumberland; scapolite, in Norway; arctizite, or wernerite, in Sweden, Norway, Switzerland; and lazulite.

FOURTH GENUS.

CLAY Genus.

First Species. Jasper.

This is divided into six sub-species; Egyptian jasper, striped jasper, porcelain jasper, common jasper, agate jasper, and opal jasper.

Second Species. Opal.

Werner divides this into four sub-species, pre cious opal, common opal, semi-opal, and wool opal.

Third Species. Pitch stone.

The colours are black, green, brown, red, and Occasionally grey. It occurs always massive in great beds and rocks. Internally, its lustre is shining. It is commonly translucent in a small degree, brittle, and pretty easily frangible.

Pitch-stone is fusible without addition: occurs in beds of the newest porphyry and floetz trap formation; and is found in Saxony, Hungary, in several of the Hebrides, and in Dumfriesshire. Some of its varieties bear a striking resemblance to pitch, from whence it receives its appellation.

Fourth Species. Obsidian.

-The principal colour is velvet-black. It alwar occurs in angularly roundish-pieces. Internally it is splendent. Some of the varieties are translucent. others semi-transparent. It is hard, easily frangi. ble, and not very heavy.

Obsidian occurs insular in the newer porphyry formation, and is found in Hungary, Iceland, in Peru, and various other countries. When cut and polished, it is sometimes used for ornamental par poses, and mirrors for telescopes have been formed of it. It probably owes its origin to fire.

Fifth Species. Pearl-stone.

Its colour is generally grey, sometimes black and red. It occurs vesicular, and the vesicles are long and roundish, with a shining pearly lustre. It is translucent on the edges, not very brittle, very easily frangible, and rather light.

Pearl-stone is found in beds of porphyry, near Tokay, in Hungary, in the north of Ireland, ard the Hebrides.

Sixth Species. Pumice-stone.

Its usual colour is a light yellowish-grey, passing into different neighbouring shades. It is small, and lengthened vesicular: its internal lustre glistening, generally translucent in the edges, soft, and seldom semi-hard, very brittle, easily frangible, and! swims in fluids.

It occurs in various situations, generally accompanied by rocks that belong to the floetz trap formation; and though usually classed among vol canic productions, in some situations it evidently is of aquatic origin. It is found in the Lipari islands, in Hungary, Iceland, and on the banks of the Rhine; and is used for porshing stones, metals, glass, and ivory; and alse for preparing parchment.

Seventh Species. Felspar

Is divided into four sub-species; compact felspar, common felspar, adularia, and Labradore

stone.

Eighth Species. Pure Clay.

Is snow white, with occasionally a yellowish tinge, and occurs in kidney-shaped pieces, which have no lustre. It is opaque, soils very little, adheres slightly to the tongue, is light, and intermedis ate between soft and friable.

Pure clay is found immediately under the soil, accompanied with foliated gypsum and s lenite, at Halle, in Saxony, only.

Ninth Species. Porcelain Earth.

The colour is generally a reddish-white, of various degrees of intensity. It occurs massive and disseminated; its particles are fine and dusty, slightly cohering, and feeling fine and light.

It is found in beds in gneiss, accompanied with quartz and other substances, in Saxony, at Passau, Limoges, and in Cornwall. In China and Japan, where it is called kaolin, it is very abundant. It forms the basis of china ware.

Tenth Species. Common Clay.

This is divided into six sub-species, as follow: 1. Loam, of a yellowish grey colour, frequently spotted with yellow and brown, and occurring massive. It is dull and weakly glimmering, colours a little, adheres pretty strongly to the tongue, and feels slightly greasy. It is often mixed with sand, gravel, and iron ochre.

2. Potter's clay is of two kinds, earthy and slaty. The earthy is of a yellowish and greyish-white colour in general; occurs massive; is opaque, colours a little, feels somewhat greasy, and adheres strongly to the tongue. Slaty potter's clay is generally of a dark ash-grey colour, and feels more greasy than the prece ling. It occurs in great rock masses, and in alluvial land. Both kinds are universally distributed, and are of great importance in the arts and in domestic economy.

3. Pipe clay is greyish-white, passing into yellowish-white, occurring massive, of a glimmering lustre, and having its particles pretty coherent. It feels rather greasy, is easily frangible, and adheres pretty strongly to the tongue.

4. Variegated clay is commonly white, red, and yellow, striped, veined, and spotted. It occurs massive, is soft, passing into friable, feels a little greasy, and adheres somewhat to the tongue. It is found in Upper Lusatia.

5. Clay-tone is commonly grey or red, with various intermediate tints. It occurs massive, is dull, opaque, soft, pretty easily frangible, feels rather meagre, and does not adhere to the tongue. It forms vast rock masses, occurs in beds and veins, and is found in Saxony, in Scotland, and in Shetland.

6. Slate clay is of a grey colour, presenting several varieties. It is massive, internally dull, opaque, pretty soft, mild, easily frangible, adheres a little to the tongue, and feels meagre. It is generally found wherever the oval, floetz trap, and alluvial formations occur.

Eleventh species. Polier, or polishing-stone,

Is of a yellowish-grey colour, striped, and the colours alternate in layers. It occurs massive, is dull, very soft, adheres to the tongue, feels fine but meagre, and is nearly swimming. It is found in the vicinity of pseudo-volcanoes, though hitherto it has only been discovered in Bohemia.

Twelfth species. Tripoli

Is of a yellowish-grey colour, passing into ashgrey; occurs massive, is internally dull, very soft, feels meagre and rough, does not adhere to the tongue, and is rather light. It is found in veins and beds in floetz rocks in Saxony, in Derbyshire, and many other countries besides Tripoli, from whence it was first brought. Its use in polishing ractals and minerals is well known.

Thirteenth species. Alum-stone

Is of a greyish-white colour, occurs massive, shews a tendency to crystallization, is soft, passing to friable, and light. It is found at Tolta, near Rome, from whence the famous Roman alum is manufactured.

Fourteenth species. Alum-earth.

The colour is a blackish-brown, and brownishblack; it is massive, dull, feels a little meagre, and somewhat greasy; is intermediate between soft and friable, and light. It is found in beds of great magnitude in alluvial land, and in floetz trap formation in several parts of Germany, in Naples, and in France. It is lixiviated to obtain the alum it contains.

Fifteenth species. Alum-slate

Is divided into two sub-species, as follow: 1. Common alum-slate is between a greyish and blueish-black colour, occurs massive, and in balls, VOL. VIII.

is soft, not very brittle, easily frangible, and not very heavy.

2. Glossy alum-slate is of an intermediate colour, between blueish and iron-black; occurs massive, with a shining semi-metallic lustre, and in other respects resembles the former. It is found in beds and strata in Saxony, France, Scotland, and Hungary; and affords considerable quantities of alum.

Sixteenth species. Bituminous shule

Is of a brownish-black colour, and occurs massive. Internally, its lustre is glimmering; it is very soft, rather mild, feels rather greasy, is easily frangible, and not particularly heavy.

It is found with clay slate in the coal formation, in Bohemia, England, Scotland, and other coal

countries.

Seventeenth species Drawing slate, or black

chalk.

Its colour is a greyish-black, with a tinge of blue; it occurs massive, is opaque, colours and writes, is soft, mild, easily frangible, feels meagre but fine, and is rather light.

It is found in primitive mountains in France, Germany, Iceland, Scotland, and the Hebrides. When of a middling degree of hardness, it is used for drawing.

Eighteenth spesies. Whet-slate.

The common colour is greenish-grey; it is massive; internally, weakly glimmering, semi-hard, feels rather greasy, and is not particularly brittle or heavy. It occurs in primitive mountains in Saxony, Bohemia, and the Levant. When cut and polished, it is used for sharpening knives and tools.

Nineteenth species. Clay-slate.

Its principal colour is grey, of which there are many varieties. It occurs massive; internally its colour is glistening, the substance opaque, seft, pretty easily frangible. It is found in vast strata in primitive and transition mountains in many different countries, but particularly in Scotland. When split into thin and firm tables, it is used for roofing houses, and other purposes.

Twentieth species. Lepidolite.

Its colour is a kind of peach-blossom, red, verging on lilac-blue, and occurs massive. Its internal lustre is glistening; it is translucent, soft, easily frangible, and easily melts before the blowpipe. it lies in gneiss. Hitherto it has only been found in Moravia, where

Twenty-first species. Mica, or Glimmer.

Its common colour is grey, of great variety of shades. It occurs massive, disseminated in thin tables and layers in other stones, and crystallized either in equilateral six-sided tables, or in six-sided prisms. The surface of the crystals is splendent; internally, shining and splendent. In thin plates, it is transparent; but in larger masses only translucent on the edges. It is semi-hard, feels smooth but not greasy, elastically flexible, and more or less easily frangible.

It forms one of the constituent parts of granite, gneiss, and mica slate, and is almost peculiar to the primitive mountains. It was formerly used instead of glass, for windows and lanterns.

Twenty-second species. Pot-stone.

Its colour is a greenish-grey, of different degrees

E

of intensity; is massive; lustre, internally, glistening and pearly, translucent on the edges; soft, feels greasy, and is very difficultly frangible.

It occurs in beds, or is indular; and is found in the country of the Grisons, in Saxony, and probably in Hudson's-bay, and is nearly allied to indurated talc.

Twenty-third species. Chlorite,

Which see.

Twenty-fourth species. Hornblende, Which see.

Twenty-fifth species. Basalt.

The usual colour is greyish-black, of various grees of intensity. It occurs massive in blunt and rolled pieces, and sometimes vesicular. Internally, it is commonly dull. It is usually found in distinct concretions, which are generally columnar,, and sometimes upwards of 100 feet in length. Commonly opaque, semi-hard, brittle, very difficultly frangible, melts without addition, and is almost exclusively confined to the floetz trap formation. It occurs in strata, beds, and veins, in almost every quarter of the globe, and is very abundant in Scotland, Ireland, and in other parts of the British European dominions. It is useful for building, as a touch-stone, as a flux, and in glass manufac

tures.

Twenty-sixth species. Wacke.

The colour is a greenish-grey, of various degrees of intensity. It occurs massive and vesicular, is dull, somewhat glimmering, opaque, usually soft, more or less easily frangible, and not particularly heavy.

It is said to belong exclusively to the floetz trap formation, where it occurs in beds and above clay, and also in veins. It is found in Saxony, Bohemia, and Sweden.

Twenty-seventh species. Clink-stone

Is commonly of a dark greenish-grey colour, always massive, and occurring in irregular columns, and tabular distinct concretions. It is usually translucent on the edges, brittle, easily frangible, and when struck with a hammer sounds like a piece of metal.

It is said to belong to the floetz trap formation, and generally rests on basalt. It is found in Lusatia, Bohemia, South America, and in the isle of Lambash, in the frith of Clyde.

Twenty-eighth species. Lava

Is divided into two sub-species:

1. Slag lava is of a greyish-black colour, passing into other shades. Externally it is spotted, occurs vesicular and knotty, is generally opaque, semihard, brittle, easily trangible, and not particularly heavy.

2. Foam lava is of a dark greenish-grey colour, occurs small and fine, vesicular; externally, glimmering, slightly translucent on the edges, brittle, easily frangible, and light. It has often been confounded with pumice-stone, from which, however, it differs very much. On account of its lightness, it is used with advantage in arching vaults and other kinds of building.

Twenty-ninth species. Green Earth.

Its colour is a celaden green, of various degrees of intensity. It occurs massive, in angular and globular pieces, and also disseminated. Internally, it is dull, streak glistening, very soft, easily frangible, and light.

Thirty-first species. Rock Sonp

Is of a brownish or pitch-black colour, massive like drawing-slate, is easily frangible, and adheres and disseminated, dull, opaque, does not soil, writes strongly to the tongue.

formation, in Poland, and in the isle of Sky, but is It is found imbedded in rocks of the floetz trap very rare, and found only in small quantities.

Thirty-second species. Yellow Earth.

The colour is ochre-yellow, of different degrees of intensity; it is massive, streak somewhat shining, soils, writes, is very soft, adheres pretty strongly to the tongue, and feels somewhat greasy. It occurs in beds with iron-stone, in Upper Saxony, and is employed as a pigment.

To the clay geaus, likewise, belong adhesive slate, float-stone, pinite, and umber, which may be considered as recent discoveries.

FIFTH GENUS.

TALC Genus.

First Species. Bole.

Its colour is cream-yellow, passing into various other shades; is commonly massive, very soft, easily frangible, feels greasy, gives a shining streak, adheres to the tongue, and is light. It occurs in rocks belonging to the newest floetz trap formation, and is found in beds of wacke or basalt, in Silesia, Italy, &c. It was formerly employed in medicine, but is now used only as a pigment.

Second species. Native Talc Earth.

The colour is yellowish-grey, passing into creamyellow. It occurs massive, tuberose, and of other shapes; is internally dull, almost opaque, soft, frangible without much difficulty, and adheres a little to the tongue.

It is found in beds of serpentine, but only hitherto in Moravia.

Third species. Meerschaum.

The usual colour is yellowish-white. It occurs massive, is internally dull, opaque, streak shining, is soft, adheres strongly to the tongue, feels a little greasy, and is nearly swimming. It is principally found in Natolia, in Samos, Hungary, Moravia, Spain, and America. It is much used in the manufacture of heads of tobacco-pipes. It is said that the Turks eat it as a medicine.

Fourth species. Fuller's Earth.

The colours are greenish-white, grey, olive, and oil-green. It is massive; internally dull, usually opaque, gives a shining streak, is very soft, feels greasy, and is not particularly heavy.

The principal colour is white, of which it presents many varieties. It occurs massive, disseminated, in crusts, and crystallized in six-sided prisms. Internally it is dull, streak shining, very soft, rather difficultly frangible, and feels greasy.

It is found in beds and veins in serpentine in Norway, Sweden, Saxony, England, Scotland, and China. It is used in the manufacture of porcelain, and for other purposes.

Seventh species. Serpentine, Which see.

Eighth species. Schiller-stone.

Its colour is alive-green, usually disseminated and massire; lustre shining, is soft, slightly brittle, and easily frangible. It occurs imbedded in serpentine, and is found in the Harz, in Saxony, Cornwall, and Ayrshire. It is often confounded with Labradore hornblende.

Ninth species. Talc.

This is divided into three sub-species.

1. Earthy tale is of an intermediate colour between greenish-white and light greenish-grey; friable, strongly glimmering, soils a little, feels rather greasy, and occurs in tin veins near Freyberg in Saxony.

2. Common or Venetian talc is principally of an apple-green colour, massive and disseminated, and in delicate and small tabular crystals. It is almost always splendent and shining, translucent,

in this leaves transparent, flexible, but not elastic; soft, easily frangible, feels very greasy, and ap

proaches to light.

It is almost wholly confined to the primitive mountains, where it is found imbedded in serpentine, and also in veins. It is found in the Tyrolese Alps, in Switzerland, and in Saxony.

3. Indurated talc is of a greenish-grey colour, of various degrees of intensity, oceurs massive, is shining, passing to glistening, strongly translucent on the edges, soft, feels rather greasy, and is frangible without particular difficulty. It is found in primitive mountains in Tyrol, Austria, Scotland, and the Shetland isles.

Is divided into the following sub-species: 1. Asbestous actynolite is of a greenish-grey colour, occurs massive, disseminated, and in capillary crystals; is internally glistening, translucent on the edges, soft, brittle, not easily frangible, nor particularly heavy. It is found in mineral beds in Saxony, and other parts of Germany.

2. Common actynolite is generally of a green leak-colour, passing into other shades of the same; it occurs massive, and likewise crystallized in very oblique six-sided prisms, is splendent externally, semi-hard, rather brittle, and not easily frangible.

It is found in beds in primitive mountains, in Saxony, Switzerland, Norway, and Scotland.

3. Glassy actynolite is principally of a mountain-green colour, of various degrees of intensity; occurs massive, or in thin six-sided acicular crys tals, is shining and vitreous, strongly translucent, brittle, easily frangible, semi-hard, and is found in similar situations with the preceding.

Thirteenth species. Tremolite,

This is divided into the following sub-species: 1. Asbestous tremolite is of a whitish colour

with a tinge of yellow, grey, red, or green: it ocinternally glistening, very soft, easily frangible, and curs massive, and in capillary and acicular crystals;

translucent on the edges.

2. Common tremolite is nearly of the same colour as the preceding, occurs massive, and in long and. very oblique four-sided prisms: internally, is shining and glistening, translucent and semi-transparent, semi-hard, and pretty easily frangible.

3. Glassy tremolite is yellowish, reddish, greyish, and greenish-white; occurs massive, and crystallized. Internally, is shining and pearly; is composed of very thin prismatic concretions, which are again collected into very thick prismatic concretions. It is translucent, brittle, and pretty easily frangible, and is said to emit a phosphoric light when rubbed in the dark.

Tremolite is principally found imbedded in primitive mountains, particularly the mountains of Tremola, in Switzerland. It is also found in different parts of Germany, and in Scotland. Sahlite, lately discovered in Sweden, likewise belongs to the talc genus.

SIXTH GENUS.

CALC Genus.

First species. Rock Milk.

dully, dusty particles generally weakly cohering, Its colour is yellowish white; it is composed of feels meagre yet fine, soils very much, and is very light. It is found in fissures and holes of moun tains composed of floetz lime-stone, in Switzerland.

Second species. Chalk.

Its colour is principally all yellowish-white: it occurs massive, disseminated, and as crust over flint. Internally, is dull, opaque, soils, writes, soft, sometimes very soft, very easily frangible, feels acids, and is found principally on the sea-coast, meagre, and rather rough; effervesces strongly with though the Chiltern range in England is wholly composed of it. It is used for polishing and cleansing metals, glass, &c. and in some places as a manure, and cement in building.

Third species. Lime-stone

Is divided into several sub-species:

1. Compact lime-stone is of two varieties, common compact lime-stone, and roe-stone. The former is generally of a grey colour, but is frequently veined, zoned, striped, or clouded; occurs massive, and in rolled pieces; is translucent on the edges, semi-hard, brittle, pretty easily frangible; is almost entirely confined, like lime in general, to the floetz mountains; occurs in sand, stone, and coal formations, in England, Scotland, and many other countries; and is frequently used for building or making roads, or when burnt, for manure and cement.

The latter, or roe-stone, is of a chesnut-brown

colour, is massive; internally dull, composed of sunall and fine-grained globular distinct concretions; semi-hard, brittle, not very easily frangible; occurs in beds in considerable quantities in Saxony, and is solely used for manure, for which its admixture with marle admirably fits it.

2. Foliated lime-stone is likewise of two kinds, granular lime-stone, and cale spar. The former is commonly whitish, but presents many varieties of that colour; is massive, occurs almost always in granular distinct concretions, is more or less translucent, semi-hard, brittle, easily frangible, is peculiar to the primitive and transitive mountains, and is chiefly found in Italy, whence it is distributed over Europe, for the purpose of statuary. The white marble of Paros, or granular limestone, has long been celebrated. Scotland furnishes some beautiful varieties of marbles, whose uses are well known.

The latter, or cale spar, is principally white, but has many shades. It occurs massive, disseminated, and crystallized, either in six-sided prisms or three-sided prisms. The lustre alternates from splendent to shining and glistening, and is most commonly vitreous. The massive varieties are translucent, and sometimes even transparent. It is found venigenous in almost every rock from granite to the newest floetz trap, occurs in a great variety of mineral veins, and is very universally disseminated, but is found particularly beautiful in Derbyshire, in Ireland, Saxony, France, and Spain.

3. Fibrous lime-stone, is of two varieties, common fibrous lime-stone, and fibrous lime-stone, or cale sinter. The former is commonly greyish, reddish, or yellowish-white; massive, lustre glistening, fragments splintery, more or less translucen', semi-hard, and occurs only in small veins.

The latter, or cale sinter, is principally white, of which it exhibits several beautiful varieties; occurs massive, and also in many particular external forms; internally is glimmering and pearly. It is commonly found in curved lamellar distinct concretions, is more or less translucent, semihard, brittle, and easily frangible; it is discovered in almost every lime-stone country. The grotto of Antiparos, and similar situations, afford striking instances of cale sinter. It is the alabaster of the ancients, and is still used in statuary.

4. Pen-stone is commonly yellowish-white, massive, internally dull, opaque or translucent on the edges; soft, very easily frangible; and is found in great masses in the vicinity of the bot springs at Carlsbad in Bohemia. It is composed of spherically round distinct concretions. All the varieties of lime-stone effervesce with acids.

Fourth species. Schaum, or foaming earth,

Is principally of a light yellowish colour; occurs massive and disseminated; is intermediate between shining and glistening; presents large, coarse, small, and fine-grained distinct coneretions; is generally opaque, soft, completely friable; feels fine, but not greasy, and cracks a little. It is found in cavities of the oldest floetz lime-stone in Thuringia, and in the north of Ireland.

Fifth species. Slate spar.

Its enlour milky, and greenish or reddish-white; occurs massive; lustre intermediate between shining and glistening, and completely pearly; fragments slaty, translucent, soft, and pretty easily rangible. It is found in lime-stone beds in primi

tive mountains, and is produced in Norway, Saxony, and Cornwall.

Sixth species. Brown spar.

This is divided into the following sub-species: 1. Foliated brown spar, is principally white and It occurs red, with several varieties of each. massive, globular, with tabular impressions, and frequently crystallized, externally shining, internally alternating from shining to splendent. It is found in granular distinct concretions of all magnitudes; is more or less translucent, semi-hard; a little difficultly frangible, and occurs in veins generally accompanied with cale spar, &c. in the inimes of Norway, France, Germany, England, and other countries.

2. Fibrous brown spar is of a flesh-red, passing into rose-red; occurs massive, lustre glistening, fragments splintery, in other respects resembling the preceding. Hitherto it has been found only in Hungary and Transylvania,

Seventh species. Rhomb spar..