Essay on Virtue of Stones and Gems – Robert Boyle



THough it will not perchance prove very difficult to propose to you my Conjecture about the Causes of the Vertues of Precious Stones; yet I fear it will not be easy for me to acquaint you fully with the Grounds of it. For unless I should transcribe for you my whole Discourse of the Origine of Mi∣nerals in General (of which you know Stones make a part I cannot well lay before you all the Considerations, by which I have been induc’d to take the Conjecture or Hypothesis I am about to propound:

And consequently I can∣not well comply with your curiosity about Gems, without either omitting several things which might much coun∣tenance the following Discourse, or proposing (without amply proving them,) some things, that I confess seem not cleer, nor some of them so much as probable, by their own Light.

But since you will have it so; I will, rather than disobey you, present you in one Discourse several things concerning Gems, whereof some belong to others of my little Tracts about the Origine of Minerals from Fluid or at least Soft Bodies; thô some indeed were more directly written concerning Gems: not∣withstanding that they were deliver’d not as an entire Tract about that subject, but as Corollaries that might be drawn from, and applications that might be made of, what had been in a more general way discours’d about the origi∣nation of Stones and other Minerals.

And therefore presuming that you will suppose with me in this Discourse some few particulars, that, I think, I have elsewhere made probable, and might perhaps do so from some of the Phae∣nomena mentioned in this Writing it self, I would immediately address my self to the subject of it, if I did not think a previous Admonition very requisite.

For, I must at the very entrance of this Discourse desire you to take notice, that when I propose my Conjectures about the Virtues of Gems, I do not suppose the truth of all, or so much as the tenth part of those wonderful pro∣perties, that Men have been pleased to ascribe to them. For not only some of the Writers of Natural Magick, but men of note, who should be more cau∣tious and sober, have delivered in their Writings many things concerning Gems, which are so unfit to be credited, and some of them perhaps so impossible to be true, that I hope the Believers of them will among the Votaries to Philo∣sophy be as great rarities, as Gems them∣selves are among Stones.

And those that can admit such unlikely Fables, will be as much despis’d by the Judici∣ous, as Jewels can be priz’d by the Rich. For my part, I never saw any great feats perform’d by those hard and costly Stones, (as Diamonds, Rubies, Saphires,) that are wont to be worn in Rings.

But yet because Physitians have for so many Ages thought fit to receive the frag∣ments of pretious Stones into some of their most celebrated cordial Composi∣tions; because also divers eminent Men of that profession, some of them fa∣mous Writers, and some Virtousi of my own acquaintance, have by their Wri∣tings, or by word of Mouth, inform’d me of very considerable effects of some Gems, (especially Christal,) upon their own particular Observations:

And lastly, because that (as I shall shew a∣non,) I find no impossibility that at least some costly and less hard, (though in∣deed more valuable) Gems, may have considerable operations upon humane Bodies, some few of which I have had opportunity to be convinc’d of, I will not indiscriminately reject all the Medi∣cinal Virtues, that Tradition and the Writers about pretious Stones have ascribed to those Noble Minerals: Con∣tenting my self to declare in a word, that suspecting most of them to be fa∣bulous, my Conjectures aim only at giving one of the Causes of those Vir∣tues ascrib’d to Gems which Experience warrants to be real and true.

Having thus explain’d in what sense my Conjecture about the Virtues of pretious Stones is to be understood; it follows that I propose the Conjecture or Hypothesis it self; the substance of which may be compriz’d in these Two particulars: First, That many of these Gems, and Medical Stones, either were once fluid Bodies, as the Transparent ones; or in part made up of such sub∣stances as were once fluid:

And second∣ly, That many of the real Virtues of such Stones may be probably deriv’d from the mixture of Metalline and other Mineral substances, which (though un∣suspectedly,) are usually incorporated with them: And the Greatness of the  Variety and Efficacy of those Virtues may be attributed to some happy Con∣current Circumstances of that Commix∣ture.

The first of these heads relates properly to the Origine of Gems. The second, partly to that, and partly to the kinds and degrees of their Virtues.

But that any Gems, especially the hardest sorts of them, should have a la∣ter Begining, then that of the Earth it self, will probably be thought to relish of a Paradox; and I doubt not, it will pass with many for a great one, that some of these hardest of solid Bodies should have been once fluid ones or Liquors: Wherefore I shall endeavour to Countenance this Hypothesis by the following Considerations.

And first the Diaphaneity of Dia∣monds, Rubies, Saphires, and many other Gems agrees very well with this Conjecture, and thereby seems to fa∣vour it. For ’tis not so likely, that Bo∣dies that were never fluid should have that arrangement of their Constituent parts, that is requisite to transparency, as those that were once in a Liquid