A U R U M 637

other be the predominant metal, yet there is a large quantity of Silver among it, inwhich the Gold lies in its state of ore.

Native Gold, though free from the penetrating sulphurs which reduce metals to ores,is yet very seldom found pure, but has almost constantly an admixture of Silver with it,and very frequently of Copper; when it has Copper in it, it is easily discover’d, if inany considerable quantity, by its hardness; the Silver is not so easily detected in it.

Native Gold is sometimes found in pure masses of considerable size, many havingbeen found of more than a pound weight; these masles are met with in the Goldmines, and are call’d Aurum Obryzum, or Obryzium, but they are very rare; suchhowever have been found at times in the German mines.

Its more common appearance in its loose state is in form of what is call’d Gold dust ;this is native Gold in smaller masses, usually indeed very small mix’d among the sandof rivers. This is found in many parts of the world, but the greatest quantity of it isfrom Guinea: some is to be met with in the beds of some of our own rivers inScotland.

Native Gold in a middle state as to size between these two kinds, is also found inthe clifts or perpendicular fissures of the solid strata in the mountains of Chili. Thesefissures are usually fill’d up partly with a reddish marie, partly with native Gold immers’din a debas’d crystalline Stone of a blueish hue, and partly with loose native Gold, whichis usually found in flat pieces, from the size of a pea to that of a horse-bean; the quan-tity however, so far as has yet been discover’d, is not great.

These, though not unfrequent in those parts of the world where there is Gold, are how-ever far from being its most common appearance ; for it is generally, and in the greatestabundance found bedded in masses of hard stone which lie at vast depths, being oftendug at a hundred and fifty fathoms ; there is no peculiar stone in which the gold is foundin these places, but it is met with indiscriminately in several kinds; some softer, someharder, and even in earths. The richest mafles are usually of a whitish and some-what bright, but opake stone, which is a debas’d crystal containing a large quantity ofa white earth, this is often ting’d in part also with black, and sometimes with other colours;yet through all these different stains, the nature and texture of the stone may be easilydiscover’d to be the same, and often the whole variety of colours will be found in onemass. In this stone the Gold lies in a very beautiful form and a great variety of figures;some parcels of it are variously divaricated, or in form of small branch’d figures; butthese are very rare; others are variously interwoven in narrower or broader veins, and otherin small flat spangles intermix’d with specks of black ; the stone in which this is usuallylodg’d will very readily give fire with steel; and will not at all ferment with Aqua Fortis.

Beside this, however, there are many coarser stones in the mines of Peru, which holdconsiderable quantities of gold, visible in large or smaller specks; and these are of allcolours, but usually white or reddish ; the Gold in these is usually in small spangles, butthere is no certainty either in the size of the masses of pure native Gold in this or any otherstate; that of the coasts of Guinea, usually call’d Gold-dust, and commonly finer thanthe smaller sands, yet sometimes affords pieces of three or four ounces weight, and thelumps of Aurum Obryzum as it is call’d, have been found of between twenty andthirty pound weight; these things however, are not common.

Pure Gold is so fix’d in the fire, that Boerhaave inform us of an ounce of it being setin the eye of a glass furnace for two months, without losing a single grain.

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