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alternately; and the Amethyſt, which reſembles Red-wine in Colour.
LVIII. The [1]Agate alſo is an elegant
- ↑ The Agate is another of the ſemi-pellucid Stones of the Flint Claſs; it is nearly of the ſame Degree of Hardneſs with the Onyx; and differs from it, as was before obſerved, in the
I have before obſerved, in the Note on the Alabaſter, that that Stone had, from its ſimilar Uſe among the Antients, alſo the Name of this Gem; and that great Errors had been occaſioned, by later Authors not underſtanding always which of the two they meant. But this is not all the Confuſion there has been in regard to this Stone; for the Antients have, many of them, deſcribed it ſo looſely and indeterminately, that it is ſcarce poſſible, from their Writings, to fix any Characteriſtic, or ſay determinately what their Onyx was: And we find, in conſequence of this, many different Stones deſcribed as Onyxes by the Writers ſince. It is to the Honour of Theophraſtus, however, to be obſerved, that he has ſtrictly and exactly determined what this Stone was; and that if the late Writers had conſulted him, inſtead of being led into a thouſand Mazes by the leſs ſcientific Authors ſince, they would never have deſcribed Carnelians, and a multitude of other different Stones, under this Name; but have known, that the Onyx was as much a diſtinct Stone with him, as the Emerald or the Amethyſt, and as different from many of thoſe they have deſcribed under its Name, as they from one another.
From his Account we are to determine, then, that the Onyx is a Stone of a whitiſh Ground, variegated with Zones of brown: And ſuch are the true and genuine Onyxes we ſee at preſent. What may farther be added to its Deſcription is, that its Ground is often of the Colour of the human Nail, bright and ſhining; the Zones are laid in perfect Regularity, and do not, according to the Judgment of the niceſt Diſtinguiſhers of the preſent Times, exclude it from the Onyx Claſs, of whatſoever Colour they are, except red, in which caſe it takes the Name of Sardonyx: The Colour of the Ground, and Regularity of the Zones, are therefore the diſtinguiſhing Characteriſtics of this Stone: And in the laſt, particularly, it differs from the Agate, which often has the ſame Colours, but placed in irregular Clouds, Veins, or Spots.
We have our Onyxes both from the Eaſt and Weſt Indies; as alſo from Spain, Italy, and Germany; and there have been tolerably fine ones found in England.
