Commonly in all fat soyles or clayie grounds, especially in the white, there is found a kinde of stones, round or oval in form, and in bigness like unto a pigeons or hens-egg, and smaller also, _viz._ as the joynt of ones finger, on the outside black, and therefore not esteemed when it is found, but cast away as a contemptible stone. Which if it be cleansed from the earth, and beaten to pieces, looks within of a fair, yellow and in streaks, like a gold Marcasite, or a rich gold Oare, but there is no other taste to be perceived in it, then in another ordinary stone; and although it be made into powder, and boyled a long time in water, yet it doth not alter at all, nor is there in the water any other taste or colour, than that which it had first (when it was poured upon the stone) to be perceived. Now this stone is nothing else, but the best and purest Minera (or Oare) of Vitriol, or a seed of Metals; for Nature hath framed it round, like unto a vegetable seed, and sowed it into the earth, out of which there may be made an excellent medicine, as followeth. Take this Oare or Minera beaten into pieces, and for some space of time, lay or expose it to the cool air, and within twenty or thirty days it will magnetically attract a certain saltish moysture out of the air, and grow heavy by it, and at last it falleth asunder to a black powder, which must remain further lying there still, until it grow whitish, and that it do taste sweet upon the tongue like vitriol. Afterward put it in a glass-vessel, and pour on so much fair rain water, as that it cover it one or two inches; stir it about several times in a day, and after a few days the water will be coloured green, which you must powre off, and powre on more fair water, and proceed as before, stirring it often until that also come to be green: this must be repeated so often, until no water more will be coloured by standing upon it. Then let all the green waters which you poured off, run through filtring paper, for to purifie them; and then in a glass-body cut off short let them evaporate till a skin appear at the top: then set it in a cold place, and there will shoot little green stones, which are nothing else but a pure vitriol: the remaining green water evaporate again, and let it shoote as before: and this evaporating and Crystallising must be continued until no vitriol more will shoote, but in warm and cold places there remain still a deep green pleasant sweet liquor or juyce: which is the true sweet and green oyl of Vitriol, and hath all the vertues above related.