BOOK III	57
	(auripigmentum) and realgar (sandaraca). These minerals are very closely related. They form, almost always, in the same veins. They have taken the force of fire in such a fashion as to appear as if having been burnt. Orpiment is more unctuous than realgar. Native orpiment, which the Greeks call αρσενικός, varies in color and form. One variety is the color of gold and is composed of many thin layers resembling scales that appear to have been placed one on the other. It cleaves similar to gypsum. This variety, if it is not mixed with other minerals, is considered to be the finest. Dioscorides writes that it occurs at Hellespont, Mysia. Theophras-tus has left us a description of another variety that is the color of gold but occurs as a powder. This variety is of second quality. The third quality has a color approaching that of realgar and occurs in the form of lumps. Dioscorides writes that it comes from Pontus and Cappadocia. Orpiment is found in Carmania. There are two artificial species of orpiment, both brilliant. One is white with pale yellow or red veins running through it, the other is yellow but varies from black to pale red with from a few to many yellow veins through it. Each of these is made from cleavages of native orpiment to which measured amounts of native salt have been added. These minerals are first ground and then placed in two earthenware ves­sels similar to broad dishes and not too deep. They are coated inside with lead. One vessel is placed over the other and where they are joined they are sealed with mud and then heated until all the orpiment is sublimated and adheres to the upper vessel. This is repeated a second and usually a third time until the mixture becomes white. The artificial yellow species is prepared with less work. Orpiment has an acrid taste and when burnt has the odor of sulphur but this is less intense than that from realgar. Painters use the native mineral and binders use it to tint books. Minium was used for this purpose at one time. Doctors use it to remove hair. If it is allowed to remain on the skin too long it will burn and injure it.31 Native realgar also varies in color. It may be deep red, similar in color to cinnabar, or less red and in part pale yellow. It may differ in form. Sometimes it is in lumps, the most common form, or in powder according to Theophrastus. Vitruvius writes that it is mined extensively along the the boundary between Ephesus and Magnesia. The best quality does not require grinding or sieving but occurs naturally in a powder just as if it had been crushed and prepared by hand. All realgar has an odor of sulphur which becomes stronger when the mineral is crushed and strongest when it is burnt. Moreover, when burnt it gives off yellow fumes. The very best, when pure, is a deep red and has an odor of sulphur without being crushed or burnt, and can be crushed with ease. This variety comes from Pontus. Realgar can be made from orpiment in the following manner. Medium small particles of the latter are placed in an earthen jar and then 31 This is an excellent description of orpiment. Agricola was the first to use the German corruption of the Latin name, namely, operment (Interpretatio), from which the modern name has evolved.