(when not rolled by running water into a pebble form,) in angular masses of no very considerable size. Many authors have limited them to two inches at most, which is a mistake, for the adularia of our green spelt often measures three or four times the stated magnitude.

Structure, Properties, &c.

Its texture is foliated, with the edges of its thin plates, sensible to the eye, like the cat's eye, Labrador, and other chatoyante stones of this section. It reflects a silver, or mother-of-pearl light, with some fhades of intermixed colours ;-Found on mount Gothard.

The iris seems to be a variety of the same stone of a reddish brown colour, in which the yellow, purple, and blue rays predominate in its reflected light.

The gerasole is of a water colour and transparent, reflecting a blue light ;-From the island of Cy

prus.

The moon stone is 'bluish, of the cat's eye kind, but resembles that of a fish;-From Ceylon.

The Labrador is of a grey colour, generally dark, and not so hard as the above mentioned varieties ; when held in certain positions to the light, it reflects a variety of beautiful fhining colours; as lazuli blue, grafs green, apple green, &c. from a gold coloured ground;-Found on the Labrador coast, and in Rufsia, in a dark grey granite; in the provinces of Ingria and Carelia, and the granite mountains of Siberia. The green Siberian feldt spath is likewise

* An ingenious correspondent, who is well acquainted with this clafs of stones, has favoured the Editor with the following accurate

extremely curious and beautiful, reflecting, like the
adularia, a mother-of-pearl light, but without inter-
mixture of other colours. Of this people of fashion
wear buttons on their clothes, and employ it in o-

account of the Labrador spar, which will be the more acceptable to
the public, as it is but little known as yet,—
,—out of Britain especially.
"The coast of Labrador is a cold inhospitable, country, bordering
upon Hudson's Bay; and was granted by George II. to a religious
sect of people called the Moravians, who solicited and obtained it, in
order to convert to their way of thinking the few inhabitants who
had settled along the sea coast; but they soon discovered a more ma-
terial advantage in cultivating the fur trade, which they do at pre-
sent to a very considerable extent. About ten years ago, another
unlooked-for source of wealth started up, and which, if it had been pro-
perly managed, would have proved little worse than a silver mine.
Some of the English settlers walking along the borders of the inland
rivers, observed particular stones of a fhining opaline colour; these
when slit, or cut in a mill and polished, displayed all the variega-
ted tints of colouring that are to be seen in the plumage of the
peacock, pigeon, or most delicate humming birds. Some of these
beautiful stones being sent as a present to their friends in England,
soon attracted the notice of the lovers of the fine productions of nature,
who bought them up with avidity. From England, the same desire
spread all over Europe; and every collector was unhappy till he
could enrich his collection with specimens of different colours,
which are no lefs than seven, often mixed with varying tints and
fhades. Some of the larger specimens have four distinct co-
lours upon the same slab; but more generally each stone, as found
in the lump, has its own particular colour, and which most common-
ly runs through the whole. The light blue and gold is the most com-
mon; green with yellow is next; fire with a purple tinge, not so
common; the fine dark blue and silver still lefs; and fine scarlet and
purple least of all. The largest specimens yet discovered are about
three feet diameter, or round the edge; and all over one continued
gleam of colour. I have seen many blocks of it greatly larger than
the above, but they had only spots of colpur here and there
thinly scattered. The first quantity that was exposed in Edinburgh,
was in the year 1790, in a wareroom on the South Bridge, by one
Shaw, from London, a native of Aberdeenshire, who I think keeps a

ther trinkets. Found near the Lake Onega, and in the granite ridges in the government of Usinfky, twelve versts from the fortrefs of Thebank ulik. The chrystalized feldt spath in prisms, is likewise shop of natural history in the Strand; and was the same person who sold that wonder of nature, the Elastic Stone, to the honourable lord Gardenstone, and which his lordship, with his usual goodness, sent to the ingenious Mr Weir, and now forms a part of his elegant Museum in Prince's Street, New Town Edinburgh. Mr Shaw again paid us a visit so late as November 1792, when he exhibited some most bril liant specimens of Labrador spar; particularly one of five extremely bright and variegated colours; one pretty large, of the scarce fire colour with the purple tinge, and one with gold, blue, and green fhades; the first was sold to the celebrated Dr Black: the two last are in the elegant collection at Morningside. This beautiful stone when analised is found to contain a portion of calcareous matter and some particles of silver and tin; some pieces bear an exceeding high polish, but very soft upon the surface, and may be scratched with a nail or file. Some naturalists ascribe the reason of the beauty of the fhades and colours, to arise from a decaying quality in the stone; however that be, it has been turned to no other use than specimens for the cabinets of the curious, and inlaying snuff boxes; but if a proper quarry be found out in Labrador, we shall have chimney pieces of it, which will go beyond any thing the world has ever seen, as to beauty and elegance. The highest price any single specimen has as yet sold for, is twenty pounds; but a much finer could now be purchased for half the money.

66

John Jeans, the Seots fofsilist, lately discovered a spar very similar and much resembling the Labrador, in the fhire of Aberdeen; but it only displays one colour, that is the gold tinge, and is of a much softer consistency; one of the finest specimens of which is to be found in lord Gardenstone's cabinet of precious stones. This stone is arranged in parallel strata, which appear in certain lights to be of a greenish semitransparency, and white opaque, like the onyx, alternately; in other lights there are seen slight tints of a brilliant golden hue, with some very small spots like mica.

"Mr Editor, if you think the above worth a place among your clear unaffected descriptions of stones, I shall think myself happy in con- . tributing any thing worthy of such company, and I am, with res pect, yours,

A, S.

vastly curious, found in druses or solitary chrystals. Pallas pofsefses a curious hexagon prism, jointed in the middle like basaltes, and mixed with the mat ter of aqua marine and feldt spath *.

Value.

Our Labrador from five to twenty-five rubles a ring stone. The green feldt spath at about twentyfive rubles the pound, since in the mode for but tons, &c.

Clafs fourth.

EGYPTIAN PEBBLE.

HARDNESS from 13 to 11; SPECIFIC GRAVITY from 4,3 to 2,6,

Varieties and Analysis.

Gr-2,7,

EGYPTIAN PEBBLE, H 13, Sp Gr- 2,7, white with dentroides. ONYX, H 13, Sp Gr 2,6, nail coloured with white and black inner zones, AGATE, H 12; Sp Gr from 2,6 to 2,5, variegated with different colours. MоCHO STONE, H 12, white with fine arborizations. SIEVE STONE, H 12, pierced like a AIGLE STONE, H 12, one

sieve in appearance. pebble containing another, both agate. SWALLOW STONE, H 12, small agate jasper pebbles, like lentiles, commonly checquered red and white. N. B. It is to this section that the author's curious ring properly belongs, although mentioned in the section Opal, as it is a black zoned onyx, crowned with a

* Pallas's prism of felt spath and aqua marine, is of the length and thickness of the thumb.

gree of hardness and transparency; so that I fhall give layer of cohosong, containing an opal as if set in it by art. CALCEDONY, HII, whitish, or bluish, and cloudy. CALCEDONY of Ferro, Sp Gr 4,3, Arg 16, Sil 84, (Bergman.) Another CALCEDONY, Arg 16, Sil 83,3, Cal 11, Iron 4, (Beindheim.) VITREOUS CALCEDONY, or DEMI OPAL, Arg a little, Sil 941, Cal 3, Iron 5, (Born catalogue.) CARNELIAN, H 11; Sp Gr from 2,6, to 2,2 red, yellow, and white. SARDONYX, H 12, white and red in zones, composed of calcedony and carnelian. CACHELONY, H 11, opaque and milk white.

Form.

The Eyptian pebble is beautifully ornamented with dentriodes, like the mocho; and although an opaque flint, certainly merits a place here, as well as the more transparent species, or agates; especially as the next valuable individual of the flint family must be excluded, if opacity is a test of rejection, viz. onyx, à species of opaque agate of the colour of the human nail, with lines or zones of a different colour, and the greater contrast the zones make with the stone, the higher is its value for cutting into portraits, &c. It is then called camebuya.

a

It is found in Egypt and East Indies, as well as in many other parts of the world, but the two first have been preferred by both ancients and moderns on account of their superior hardness. The different parts of Europe where they are found would occupy too much space: Sky, one of the Western Islands, may be mentioned, as the fine onyxes of that neglected spot are little known to natural