Earths and green, or leek green. Streak greenish. It neither be Stones. comes electric by friction nor heat *. Before the blowpipe it melts into a black glafs. A fpecimen of black Hauy, Four. de hornblende, analyd by Mr Hermann, was compofed of Min. N° 37 filica, xxvii. 267. 27 alumina, 25 iron, 5 lime.

+ Beob. der

Berlin, S. Band 317. 54

Refplendent horn

blende.

* Kirw. i.

221.

+ Bergbaukunde, Band. P. 92.

55 Obfidian. Kirw. i. 264.

į Berg. iii.

204.

56

Petrilite.

*Kirw. i. 325.

57 Felite.Kirw. i. 326.

3 magnesia, 97 t

SPECIES 10. Refplendent Hornblende. There are two minerals which Werner confiders as varieties of hornblende, and Mr Kirwan as conflituting a diftin&t fpecies. Thefe, till future analyses decide the point, we shall place here under the name of refplendent hornblende, the name given them by Mr Kirwan; and we shall defcribe them separately.

Variety 1. Labradore hornblende. Texture, curved foliated. Luftre, in fome pofitions, o; in others metallic, and from 3 to 4. Opaque. Hardness 8 to 9. Sp. gr. from 3.35 to 3.434. Colour, in moft pofitions, greyish black; in others, it reflects a strong iron grey, fometimes mixed with copper

red.

96.5 +

is amorphous. Texture fomewhat foliated. Fracture Simple uneven, approaching to the splintery. Luftre 1. Tranf Stores parency fcarce 1. Hardness 9. Colour azure blue, and fometimes brown and green. Streak white. Before the blow-pipe, whitens and becomes rifty; but is infufible per fe.

GENUS VII. SAP.

SPECIES 1. Felspar ‡.

G VIL S Felfjar

Four, de

11. 401.

Mem

This ftone forms the principal part of many of the Kiru. i, highest mountains. It is commonly cryftallized. Its 16. and primitive form, according to De Lifle, is a rectangular phy prifm, whose bafes are rhombs, with angles of 65 and fim. 115°t. Sometimes the edges of the prifm are wanting, fig-13, and faces in their place; and fonetimes this is the cafe and 14. alfo with the acute angles of the rhomb. For a defcription and figure of thefe, and other varieties, we refer the reader to Romé de Lifle *, Mr Hauy †, and Mr * Cryfall, Pixit. Its texture is foliated. Its cross fracture uneven. Par 174 Fragments rhomboidal, and commonly fmooth and po- p. 173 lifhed on four fides. Luftre of the polifhed faces often Sarde 3. Transparency from 3 to 1. Hardnefs 9 to 1o. Sp. Neuvent gr. from 2.437 to 2.7. Gives a peculiar odour when Cr rubbed. It is made electric with great difficulty by friction. Fufible per fe into a more or less tranfparent glafs. When cryftallized, it decrepitates before the blow pipe. Pure Fellpar. Moon flone-Adularia.

Variety 1.

This is the pureft felfpar hitherto found. It occurs in Ceylon and Switzerland; and was first mentioned by Mr Sage. Luftre nearly 3. Tranfparency 2 to 3. Hardnets 10. Sp. gr. 2.559. Colour white; fome. times with a fhade of yellow, green, or red. Its furface is fometimes iridescent.

Variety 2. Common Fellpar.

Luftre of the cross fracture o; of the fracture, in the

to 1. Colour molt commonly flefh red; but often bluish grey, yellowish white, milk white, brownish yellow; and fometimes blue, olive green, and even black.

Variety 3. Labradore felfpar.

This variety was discovered on the coat of Labradore by Mr Wolfe; and fince that time it has been found in Europe. Luftre 2 to 3. Tranfparency from 1 to 3. Sp. gr. from 2.67 to 2.6925. Colour grey. In certain pofitions, fpots of it reflect a blue, purple, red, or green colour.

Variety 4. Continuous fellpar.

This variety moit probably belongs to a different fpecies; but as it has not hitherto been analyfed, we did not think ourselves at liberty to alter its place.

It is found in large maffes. Texture earthy. Frac ture uneven, fometimes fplintery. Luftre o. TransHardness 10. parency 1. Sp. gr. 2.609. Colour reddish grey, reddifh yellow, fleth red. A fpecimen of green felfpar from Siberia, analysed by Vauquelin, contained

Ann. de Clim. 111 SPECIES 100.

Earths and

Stones.

59

ii. 196.

108.

SPECIES 2. Lepidolite (F). Lilalite.

tween 1 and 2.

This ftone appears to have been firft obferved by the Lepidolite. Abbé Poda, and to have been first defcribed by De § Grell's An- Born f. Hitherto it has only been found in Moravia nals, 1791, in Germany, and Sudermania in Sweden *. There it *Beyer, is mixed with granite in large amorphous maffes. It is Ann. de compofed of thin plates, eafily feparated, and not unlike Clim. xxix. thofe of mica +. Luftre, pearly 3. Tranfparency be Hardnefs 4 to 5. Not eafily pulve↑ Le Lievre, rifedt. Sp. gr. from 2.816 || to 2.8549 . Colour Four, de Min. No li. of the mafs, violet blue; of the thin plates, filvery white. Powder white, with a tint of red §. Before the blowIbid. pipe, it froths, and melts eafily into a white femitranfpa{| Klaproth. rent enamel, full of bubbles. Diffolves in borax with Hauy. Le Lievre, effervefcence, and communicates no colour to it *. Ef. Four de fervefees flightly with foda, and melts into a mafs spotted Min. No li. with red. With microcofmic falt, it gives a pearl coloured globule †.

219.

219.

#Ibid

+ Klaproth,

Ann. de

This ftone was firft called lilalite from its colour, that of the lily. Klaproth, who difcovered its component Chim. xxii. parts, gave it the name of lepidolite (G). It is compofed of

37.

Vauquelin,

Ann. de
Chim. XXX.

Ics.

60 Leucite.

255.

53 filica, 20 alumina,

18 potafs,

SPECIES 3. Leucite .

Vefuvian of Kirwan-White garnet of Vefuvius. This ftone is ufually found in volcanic productions, Kirw. i. and is very abundant in the neighbourhood of Vefuvius. It is always cryftallized. The primitive form of its cryftals is either a cube or a rhomboidal dodecahedron, and its integrant molecules are tetrahedrons; but the varieties hitherto obferved are all polyhedrons: The moft cominon has a fpheroidal figure, and is bounded by 24 ↑ Fig. 15. equal and fimilar trapeziods t; fometimes the faces are 12, 18, 36, 54, and triangular, pentagonal, &c. For a defcription and figure of feveral of thefe, we refer the Four de reader to Mr Hauy . The cryftals vary from the fize Min. No zxvii. 185. of a pin head to that of an inch.

Stones

It was by analysing this ftone that Klaproth difco- Simple vered the prefence of potafs in the mineral kingdom; which is not the least important of the numerous difcoveries of that accurate and illuftrious chemift.

Leucite is found fometimes in rocks which have never been expofed to volcanic fire; and Mr Dolomieu has rendered it probable, from the fubftances in which it is found, that the leucite of volcanoes has not been formed by volcanic fire, but that it exifted previously in the rocks upon which the volcanoes have acted, and that it was thrown out unaltered in fragments of these rocks §. GENUS VIII. SAG. SPECIES 1. Emerald (×).

This ftone has hitherto been only found crystallized. G.VIII. SAG The primitive form of its cryftals is a regular fix-fided Emerald. prifm; and the form of its integrant molecules is a tri. angular prifm, whofe fides are fquares, and bafes equilateral triangles. The moft common variety of its ftals is the regular fix-fided prifm, fometimes with the edges of the prifm, or of the bafes, or the folid angles, 72. or both wanting, and small faces in their place +. The Fig. 16. fides of the prifm are generally channelled. + Romé de Its texture is foliated. Its fracture conchoidal. Luftre Lile, ii. ufually from 3 to 4. Tranfparency from 2 to 4. Caufes a double refraction. Hardness 12. Sp. gr. 2.65 to 2.775. Colour green. Becomes electric by friction, but not by heat. Its powder does not phofphorefce when thrown on a hot iron f. At 150 Wedgewood Dolomieu, it melts into an opaque coloured mafs. According to Min. No Four, de Dolomieu, it is fufible per fe by the blow-pipe.

This mineral was formerly fubdivided into two diftin&t Ibid. fpecies, the emerald, and beryl or aqua marina. Hauy demonftrated, that the emerald and beryl correfponded exactly in their structure and properties, and Vauquelin found that they were compofed of the fame ingredients; henceforth, therefore, they must be confidered as varieties of the fame fpecies.

The variety formerly called emerald varies in colour from the pale to the perfect green. When heated to 120° Wedgewood, it becomes blue, but recovers its colour when cold. A fpecimen, analyfed by Vauquelin, was compofed of

Barths and Stones.

66

G. X. 3.

SAWL.

Zeolite.

*Hauy, Four, de Min. N° ziv. 86.

GENUS X. 3. SAWL. SPECIES 4. Zeolite (N).

This ftone was first defcribed by Cronstedt in the Stockholm Tranfactions for 1756. It is found fometimes amorphous and fometimes cryftallized. The primitive form of its cryftals is a rectangular prifm, whofe bafes are squares. The moft common variety is a long four fided prifm, terminated by low four fided pyramids*.

Its texture is ftriated or fibrous. Its luftre is filky, from 3 to 1. Tranfparency from 2 to 4; fometimes 1. Hardness 6 to 8; fometimes only 4. Abforbs water. Sp. gr. 2.07 to 2.3. Colour white, often with a fhade of red or yellow; fometimes brick red, green, blue. When heated, it becomes electric like the tourHaus, ibid. malinet. Before the blow-pipe it froths (0), emits a phofphorefcent light, and melts into a white femitranf phofphorefcent light, and melts into a white femitranfparent enamel, too foft to cut glass, and foluble in acids. In acids it diffolves flowly and partially without effervefcence; and at last, unless the quantity of liquid be too great, it is converted into a jelly. A fpecimen of zeolite (P), analyfed by Vauquelin,

No xxviii.

276.

Ibid. N

aliv. 576.

67 Sulbite.

contained

53.00 filica,

27.00 alumina,

9.46 lime,

10.00 water.

99.461.

SPECIES 5. Stilbite.

This ftone was firft formed into a diftin&t fpecies by Mr Hauy. Formerly it was confidered as a variety of zeolite.

The primitive form of its cryftals is a rectangular prifm, whose bases are rectangles. It cryftallizes fometimes in dodecahedrons, confifting of a four-fided priim with hexagonal faces, terminated by four-fided fummits, whofe faces are oblique parallelograms; fometimes in fix-fided prifms, two of whofe folid angles are wanting, and a small triangular face in their place *. Its texture is foliated. The lamine are cafly fepaMin. No rated from each other; and are fomewhat flexible. Luftre pearly, 2 or 3 (Q).

Hauy,

Jour, de

xiv. 86.

Hardnefs inferior to that of zeolite, which feratches ftilbite. Brittle. Sp. gr. +Hauy, ibid. 2.500t. Colour pearl white. Powder bright white, No xxviii. fometimes with a fhade of red. This powder, when ex276. pofed to the air, cakes and adheres as if it had abforbed water. It caufes fyrup of violets to affume a green colour. When ftilbite is heated in a porcelain crucible, it fwells up and affumes the colour and femitranfparency of baked porcelain. By this procefs it lofes 0.185 of its weight. Before the blow-pipe it froths like bo. rax, and then melts into an opaque white coloured en

Vauquelin, amel §.

ibid. No zxxix. 161.

This ftone, which was discovered by Mr Dolomieu, is found cryftallized in the cavities of lava. It was firft had formerly confounded it with zeolite. made a diftinct fpecies by Mr Hauy. Mineralogifts

fometimes found cryftallized in cubes, whofe folid angles The primitive form of its cryftals is a cube. It is are wanting, and three fmall triangular faces in place of each; fometimes in polyhedrons with 24 faces. It is ufuall fomewhat tranfparent. Hardness about 8; feratches glafs flightly. Sp. gr. above 2. When rubbed, it acquires only a fmall degree of electricity, and with difficulty (R). Before the blow-pipe it melts without" frothing, into a white femitranfparent glass.

GENUS X. 4. SLA. SPECIES 7. Lazulite t.

Stones.

|| Ibid. 164.

68

Analcime,

*Hauy, Four. de Min. Noxiv S6. and

xxviii. 278. 69

This ftone, which is found chiefly in the northern parts of Afia, has been long known to mineralogifts by G.X.4.SLA. the name of lapis lazuli. This term has been contract- Lazulite. ed into lazulite by Mr Hauy; an alteration which was + Kirw. i. certainly proper, and which therefore we have adopted. 283. Its fracture uneven. Lazulite is always amorphous. Its texture is earthy. Luftre o. Opaque, or nearly fo. Hardness 8 to 9 Sp. gr. 2.76 to 2.945. Colour Brissou # and yellow from particles of pyrites. blue (s); often spotted white from fpecks of quartz, and yellow from particles of pyrites.

It retains its colour at 100 Wedgewood; in a highmafs. With acids it effervefces a little, and if previ er heat it intumefces, and melts into a yellowish black oufly caleined, forms with them a jelly. oufly caleined, forms with them a jelly. Margraff published an analyfis of lazulite in the Ber.. lin Memoirs for 1758. confirmed by Klaproth, who found a specimen of it to His analyfis has fince been

§ Beiträges i. 196.

70 G.XI. SALI. Garnet.