The philosophers stone in medieval England - an introduction

Most people will have heard of "The philosophers stone", even if just from Harry Potter.*  But few know what it is, and this page tries to give a broad idea of what it was in Medieval Europe, especially England.

Short explanation - the philosophers stone is a substance which turns base metals (lead, copper etc) into gold or silver or cures disease.

Longer explanation- in medieval England, the philosophers stone was a substance to turn other metals into gold and silver. There were only 7 
recognised metals at that time, lead, copper, iron, mercury, tin, silver and gold, and gold was acclaimed as the best, highest and most 
mature and incorruptible one, because it didn't react with anything. Because of its beauty it was rare and expensive, and so there was an 
interest in making gold in order to become rich. The quickest way to do it (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. Of course there were also elixirs for humans, since alchemy had, by the medieval period, a long 
association with medical matters. 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, or simply use the alchemical processes as an exemplar of spiritual 
progression to perfection.

So it was that apothecaries were sometimes also alchemists, including the physician of Edward the 4th in the 1460's. A further relation 
between medical and alchemical matters is that in the medieval period, health was thought to be determined by the balance of the 4 humours 
(blood, yellow bile, black bile and phlegm), and so if they were out of balance, you became ill. It was also known since the ancient Greeks 
that everything 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. 

A quick note on gold - it is the only 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 just another short step to seeing 
alchemical practices, of purifying or healing metals to perfection, as being a spiritual journey for the practitioner. Certainly this latter 
interpretation is how alchemy began 2,000 years ago, but it mutated somewhat over the centuries, and the alchemy claimed by modern 
practitioners is ultimately different to that of the early period, despite the protestations of new age types. 

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.

Which leads us to another important point.  Colour is very important to alchemists, colour being an important and obvious property of all metals, with the dullness of lead, the brightness of silver and tin and so on.  And one way you could tell that you had gold was it's colour.   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. By the medieval period the stone was always described as red, but the colours of the ingredients used were also important, so we have the green lion for example and reference to burnt alum which is white like snow.  

Therefore in order to make the stone, you have to do a lot of chemistry to make things change colour and property.  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 as well as the original distillate, 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 my 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. Other well known cover names include "green lion" for 
green vitriol (iron sulphate). In Chaucer's 1390's Canterbury Tales, a list of substances an alchemist uses is given, which includes 
mercury, sulphur, vitriol, arsenic, lead, alum, burnt bone, borax, oil of tartar, chalk, white of egg, dung, ashes and some others. So an 
alchemist would probably have fairly good experience of the properties of a wide variety of substances. 

Since around 1403-1404, using alchemy to make gold in England was illegal without a licence from the King, and Henry 6th issue one in the 1450's, 
Edward 4th issuing two in the 1460's. Edward also had an alchemist working for him on one of his manors, and one of his physicians had been 
named on the license 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 the 1470's alchemy seems to be in less exalted company, with it quieting down again until the time of Elizabeth.  But there were still alchemists such as Lord Grey of Codnor, or William Blomfild, or Thomas Charnock.  

Before reaching England, Alchemy itself had spread through Europe from translations done by monks who were interested in the Greek and Roman learning passed down 
through Moslem culture. The main centres for translations in the 12 and 13th centuries were Spain and Sicily, where Arabic manuscripts were 
translated into Latin and brought across Europe. Of course by the late 13th century Europeans were producing their own manuscripts and 
instructions on how to make the philosophers stone, but over time, as laymen became better educated, alchemy was less the province of 
educated clerics and was practised by secular people, especially so in the 15th century. The famous English example of that century being 
Thomas Norton of Bristol, who allegedly made the stone in 1461, and wrote a book about it in 1477. 

*It is important to note that Nicholas Flamel (Who is featured in the first Potter book) was almost certainly not an alchemist, and the writings attributed to him were made up in the late 16th century by Frenchmen who wanted an alchemical hero of their own. Needless to say, people often prefer the myth to the facts.