stones, I remember I rid thither and procured a workman or two to dig me up a number of them, divers of which I found to be curiously and determinately shaped, much like some crystals of nitre that I have taken pleasure to compare with them. And the like figuration I have also observed in divers Cornish diamonds, and in a fair and large one, which one that knew not what it was found growing with many lesser in Ireland, and presented me. And to let you see, that it is not only in these softer gems that this curious figuration is to be met with, I shall add, that I found among many stones I had and took to be rubies (and those, the jewellers will tell you, are exceeding hard) a considerable number, whose shapes, though not the same with those of the Cornish and Irish stones, were yet fine and geometrical. And the like I have observed even in those hardest of bodies, diamonds themselves, of which remembering that in my collection of minerals I had a pretty one that was rough, I perceived that the surface of it consisted of several triangular planes which were not exactly flat, but had as it were smaller triangles within them, that for the most part met at a point and did seem to constitute as it were a very obtuse solid angle: encouraged by this, I examined several other rough diamonds, and found the most of them to have angular and determinate shapes, not unlike that newly mentioned. And having thereupon consulted an expert jeweller, that was also a traveller, though he could not name to me the shapes of the uncut diamonds he had met with, yet he told me he generally found them to be shaped like that I showed him, insomuch that such a shape was a mark by which he usually

judged a stone to be a right diamond, if he had not the opportunity to examine it by hardness.

And this I shall add, in favour of the comparison I lately intimated betwixt the coagulation of petre and that of gems, that having once made an odd nienstruum wherein I was able to dissolve some precious stones, there shot in the liquor crystals pretty large, and so transparent and well-shaped that they might well have passed for crystals of nitre; and yet, if I much misremember not, they were insipid. And I have divers times taken notice in such stones as the Bristol diamonds, that though that part which may. be looked upon as the upper part of the stone were curiously shaped, having six smooth sides, which at the top were as it were cut off sloping so as to make six triangles that terminated like those of a pyramid in a vertex: yet that, which may be looked upon as the root or lower part of the stone, was much less transparent (if not opacous) and devoid of any regular figuration; of which the reason seems to be, that this being the part whereby the stone adhered to it's womb, it was sullied by the muddiness of it, and reduced to conform itself to whatever shape the contiguous part of the cavity chanced to be of; whereas the upper part of the stone was not only formed of the clearer part of the lapidescent juice before the waterish vehicle was exhaled, but had room and opportunity to shoot into the curious figure belonging to it's nature. And this is much more conspicuous, where many of these crystals grow as it were in clusters out of one mineral cake or lump, as I have seen not only in those soft but yet transparent concretions, which some of the later mineralists (for the

ancient seem scarcely to have known them) call Fluores, and particularly in a very fine mineral lump, that I had once the honour to have showed me by a great prince and no less great a virtuoso, to whom it was then newly presented. For this mass consisted of two flat parallel cakes, that seemed composed of a dirty kind of crystalline substance; and out of each cake there grew toward the other a great number of stones, some of which by their cohesion kept the two cakes together, and most of these stones having each of them a little void space about it wherein it had room to shoot regularly, were geometrically shaped, and which looked very prettily, were coloured like a German amethyst. And I have myself a pretty large stone, taken up here in England by a gentleman of my acquaintance, which consists as it were of four parts the lowermost is a thin and broad flake of coarse stone, only adorned here and there with very minute glistering particles, as if they were, as probably they may be, of a metalline nature; over this is spread another thin white but opacous bed, which is so enclosed between the first-named bed and the two others, that without defacing the stone I cannot well examine it: the third consists of a congeries of minute crystals exceedingly thick-set, which therefore look whitish, having little or no tincture of their own; and this part, no more than either of the former, is not much thicker than a barley-corn: the fourth and uppermost part, which yet seems in great part to be the same crystals, which as they grow higher and spread acquire a deeper colour, is made up of a great number of amethysts, some paler and some highly tincted, which are of very differing figures and bignesses, accordingly (as one may guess) as they had con

veniency to shoot-these at one end of the stone lying in a flat bed, as it were, and scarcely exceeding a barleycorn in length; whereas those at the other end shoot up to a good height into figured crystals, some of them as big as the top of my little finger, and those are the most deeply coloured, being also of a good hardness, since I found that they would easily grave lines upon glass.

'I remember also, that going to visit a famous quarry, that was not very far from a spring which had somewhat of a petrescent faculty in it, I caused divers solid pieces of rough and opacous stones to be broken, out of hope I had to find in them some finer juice coagulated into some finer substances: and accordingly I found that in divers places the solid and massy stone had cavities in it, within which all about the sides there grew concretions, which by being transparent like crystal and very curiously shaped seemed to have been some finer lapidescent juice, that by a kind of percolation through the substance that grosser stone was made of, had at length arrived at those cavities; and upon the evaporation of the superfluous and aqueous parts, or by their being soaked up by the neighbouring stone, had opportunity to shoot into these fine crystals, which were so numerous as quite to overlay the sides of the cavities, as I can show you in some large clusters of them that I brought thence. And inquiring of an ancient digger, Whether he had not sometimes met with greater quantities of them?' he told me, that he had, and presented me a great lump or mass made up of a numerous congeries of soft crystals, (but nothing so colourless as these others newly mentioned) sticking to one another, but not any of them to any part of the

rock so that they seemed to have been hastily coagulated in some cleft or cavity, as it were in a mould, where meeting and mingling before concretion with some loose particles of clay, the mass may thereby be discoloured.

Our argument drawn from the figuration of transparent stones may be much strengthened by the coalition I have sometimes observed of two or more of such stones, and the congruity in the shape of some of them to the figures of those parts of the others that were contiguous to them, and seemed to have been formed after them.'