A short explanation of what the stone is, is – the philosophers stone is a substance which turns base metals (lead, copper etc) into gold or silver. The longer explanation-
A short explanation of what the stone is, is – the philosophers stone is a substance which turns base metals (lead, copper etc) into gold or silver. The longer explanation- in medieval England, the philosophers stone was a substance reputed to have two abilities. The most commonly known is the ability to turn base metals into gold or silver. At this time there were only 7 recognised metals: lead, copper, iron, mercury, tin, silver and gold, Gold was recognised as the best, highest and most mature and incorruptible one, because it didn’t react with anything. Moreover it was quite rare, and thus expensive and of course attractive to people because of that. The quickest way to turn other metals into gold (rather than wait centuries for the earth to produce it itself) was to use an elixir, which is a type of medicine (analogies are very important at this time) for metals, making the poor, cheap and corrupt metals like copper and lead into gold. The philosopher’s stone went under many names, too many to list here.

The second purpose of the Philosopher’s stone is to make elixirs which cure human infirmity. In fact by the 15th century you could make a mineral stone for treating metals, and a vegetable or animal stone for treating people. There was a general confusion of the medicines for metals and medicine for people, such that I am at times uncertain whether the author of a text means to heal humans or make gold.So it was that apothecaries were sometimes also alchemists, including a physician to Edward the 4th. A further connection between the human and the metallic is that in the medieval period, health was thought to be determined by the quantities of the 4 humours (blood, yellow bile, black bile and phlegm), and so if they were out of balance, you became ill. It was known since the ancient Greeks that everything on earth is made up of four elements (earth, air, fire and water) and so if you changed the proportion of each element in a substance you could change it into a different substance. Hence medicines for humans and medicines for metals worked in a similar way, the four elements producing the four humours in the body, I think in the liver. Changing your diet altered the proportions of the four humours, and relatedly the Stone changed the proportion of the 4 elements to become more perfect and like gold.

What exactly the stone looked like is unclear because of differing accounts of its appearance. It is often presented as a red powder, which is thrown upon the molten metal you want to change. Or else it is an oily red liquid that is very thick and doesn’t evaporate if you leave the top off the bottle. Or some recipes have it as a liquid which can be heated until it turns into a powder and you can change it between liquid and solid. Colour is very important to alchemists, and they describe the sequence of colours seen when making the stone as each operation is carried out and ingredient added; one of the more common sequences being black, white, yellow, red. Red is the highest, perhaps a red like blood, and one alchemical illustration of the period shows bright red drops raining down upon the materials making the stone. The philosophers stone is the target, but in order to get there, you have to do lots of chemistry.
By the medieval period, it often (But there are always different recipes) involves taking metals like lead, copper, tin, mercury and heating them in air to make the oxides, dissolving the oxides in acids such as acetic or nitric acid, distilling the resulting liquid, heating what is left after the distillation, adding other liquids containing metals to it, applying more heat, and so on. After a proper sequence of these actions, you end up with a red powder or liquid which is the philosophers stone. Unfortunately, the recipes are very coy about exactly what substance is to be used, and by the medieval period alchemists are referring to “philosophers mercury” and “philosophers sulphur” and specifically saying that it is not common mercury or quicksilver, but something else.

Since around 1403-1404, practising alchemy to make gold in England was illegal without a licence from the King. Henry 6th issue one in the 1450’s, Edward 4th issued two in the 1460’s and I think there are others which I have not read about. Edward also had an alchemist working for him on one of his manors, and one of his physicians had been named on the licence granted by Henry 6th in the previous decade. Alchemically interested people in that time include even George Neville, Archbishop of York. On the other hand after Richard 3rd alchemy seemed to die away, or at least go underground, although we know of several alchemists who were around in the late 15th/ early 16th century before the next big alchemy period under Elizabeth the 1st. Quite a few people claimed to have made the stone, including Thomas Norton, George Ripley, the problem being that they made the claims in manuscripts which were popularly circulated after their deaths. Or else were used by certain believers in the processes, the sort of believer who wouldn’t ask awkward questions. Since it was also thought that only good and holy people would be given such a Donum Dei, a gift from God, asking them to prove it by making lots of gold would be a bit rude.An aforementioned licence of May 1456, printed and translated in Ambix, volume 6, 1957 by D Geoghegan, “A licence of Henry VI to Practise Alchemy”. You can see how the medical and transmutational are intertwined.

Know ye, that the sages and most famous philosophers of ancient times have taught, and recorded in their writings and books under signs and symbols, that many glorious and noteworthy medicines can be made from wine, precious stones, oils, vegetables, animals, metals, and certain minerals; and especially a most precious medicine, which some have called the mother of philosophers and Empress of medicines; others have named it the inestimable glory; others, indeed, have named it the quintessence, the philosophers stone, and the elixir of life; a medicine whose virtue would be so efficacious and admirable that all curable infirmities would be easily cured by it; human life would be prolonged to its natural term, and man would be marvellously sustained unto the same term in health and natural virtue of the body and mind, in strength of limb, clearness of memory, and keenness of intellect; moreover, whoseoever had curable wounds would be healed without difficulty; and it would also be the best and most perfect medicine against all kinds of poisons.
But also many other benefits, most useful to us and the well-being of our kingdom, could result from the same, such as the transmutation of metals into true gold and very fine silver; and whem by much frequent cognition, have considered how delectable and useful it would be, both for ourselves and the well-being of the kingdom, if precious medicines of this kind were had, with God’s grace, by the labours of learned men; also it is true that in days and years gone by, it was granted to very few, or none, to attain the true preparation of the said glorious medicines; sometimes on account of the arduous difficulties attending and surrounding the composition of the same; sometimes because fear of punishment prevented and drew away many talented men – most learned in natural sciences and very disposed to practise the same medicines – from the investigation and practise of such secrets, long since and until the present day; and turns them aside now, for fear of incurring the penalty of a certain statute of the time of Henry, our grandfather, given and provided against multipliers.

Of course where the word elixir comes from is another question, to be answered in another post.

A quick note on gold – it is the only ancient to medieval metal that when heated in a furnace until it melts, does not react appreciably with the air in the furnace. It
doesn’t corrode when left outside overnight, whereas copper roofs soon go
green, and lead roofs get a little white and need replaced every few
centuries. Iron rusts, and silver tarnishes to black, but gold just sits
there doing nothing. So it is easy to see how it became symbolic for all
sorts of cultural and spiritual things to do with permanence and purity. It
is then another step to seeing alchemical practises, of purifying or healing
metals to perfection, as being a spiritual journey for the practitioner.
Certainly this latter interpretation is probably how alchemy began 2,000 years ago, but it mutated somewhat over the centuries under the influence of the different cultures who absorbed the learning of their predecessors.