Here is required by how long time the stone is to be turned into blackness and what is the figure of true solution of the stone when blackness appeareth the first time it is figure of putrefaction and solution of the stone, but when it is vanished away and clearly gone it is a sign of the whole putrefaction of the stone and of the dissolution thereof, or else it is demanded if the black clouds endure in the foresaid stone by the space of 40 days, I answer sometimes it doth more, and sometimes less, this variation chanceth of the variety and quantity of the medicine, and according to the wisdom of the worker, wherefore the more quantity requireth more time, and the less the less.

“Donum Dei” by George Aurach, 1475


When the matter has stood for the space of forty days in a moderate heat, there will begin to appear above, a blacknesse like to pitch, which is the Caput Corvi of the Philosophers, and the wise men’s Mercury. Blacknesse once seen, thou mayst be sure a True Conjunction of the principles is made.

“Zoraster’s Cave” by Anonymous, 1667


Black colour, which is first and it is the key of the Beginning of the Work. This mass thus Blackened is the Key and sign of perfect invention.

“Verbum Dismissum” by Bernard Trevisan, 1480


But every seed is useless if it remains as it is, if it does not decay and becomes black; because corruption always precedes generation. It is this way that Nature proceeds in all its operations, and when we want to imitate it, we must also blacken before whitening, without which we will only produce rejects.

“The Light Coming Out Of Darkness By Its Own” by  Fransisco Santinelli, 1666


When in the work blacknesse appears, know that thou hast found the right way of working. Then rejoice, for God has given thee a very Great and pretious Gift.

“Zoraster’s Cave” by Anonymous, 1667


Our stone is a thing rejected, but found in dunghills, (i.e., in putrefaction, or the matter being putrefied) containing in itself the four elements, over which it triumphs, and is certainly to be perfected by human industry. Digest forty days in igne philosophorum.

“The Root Of The World” by Roger Bacon, 1250


Therefore dear Son, when thou art in thy work, see first thou have the black colour, and then art thou sure thou dost putrefy and proceedest the right way, patience and tarrying be necessary in our work. O Blessed Nature and blessed is thine operation, for of imperfect thou makest perfect with true putrefaction, which is black and obscure. Then after thou shalt make to spring new, and divers things, which thy viridity or green lion makest divers colours appear.

“Donum Dei” by George Aurach, 1475


Our vessel being warily heated at the first for fear of its cracking, an ebullition of the contained matter is brought on, so that the moisture is alternately circulated in white fumes above, and condensed below, which may continue for a month or two, nay longer, increasing the heat gradually to another degree, as your matter discovers a disposition for fixing, by the vapor continuing at longer intervals condensed, and rising in a lesser quantity, of an ash color, or other dark shades, which it will assume as a medium to perfect blackness, the first desirable stage in our harvest. With darker clouds, but quickly dissipated, and growing less in quantity, till the whole substance resembles molten pitch, or the aforesaid bituminous substance, bubbling less and less, resting in one entire black substance at the bottom of your glass. This is called the blackness of black, the head of the crow, etc., and is esteemed a desirable stage in our philosophical generation, being the perfect putrefaction of our seed, which will ere long show its vital principle by a glorious manifestation of Seminal Virtue.

“On The Philosopher’s Stone”