Of Christallo. chap. 31.
CHristall is a bright stone and cléere, with watry coulour. Men suppose yt it is of snow or Ise made hard in space of many yeres. Therfore ye Gréeks gaue a name thereto. It is gendered in Asia, & in Cipres, & namely in the North moū∣taines, where the Sun is most seruent in Sūmer: and they make this dure long, yt is called Christall. This stone set in ye Sun taketh fire, insomuch if dry tow be put therto, it setteth the tow on fire. His vse is ordeined to drink, & worketh none other thing, but what cold thing may do. Huc vsque Isi. li. 16. cap. 13. Dioscorides speaketh of Christall & saith, yt it is hard∣ned & turned into stone, not only by ver∣tue & strength of cold, but more by earth∣ly vertue, and the coulour thereof is like to Ise. The vertue therof helpeth against thirst & burning heat: and if it be beaten to pouder & dronken with hony, it filleth breasts & teates full of milke, if ye milke faileth before because of colde: Also if it be dronkē, it helpeth against Collica pas∣sio, & against the passion of euill guts, of ye wombe be not hard. The stone is cléere, & so letters and other things that be put therin, be séene cléerly inough. That chri∣stall materially is made of water. Gre∣gory saith super pri. Ezech. Water (sai∣eth he) is of it selfe fléeting, but by strēgth of cold it is turned & made stedfast chri∣stall: and so in Eccle. it is written. The Northen wind blew and made christall fréese, &c. And héerof Arist. telleth ye cause in li. Meth. Ther he saith, ye stony things of substance of oare, be water in matter, as Richardus Rufus saith. Stone oare is of water, but for it hath more of drines of earth then things that melt, therefore they be not frore onely with coldnesse of water, but also for drynesse of earth that is mingled therwith, when ye watry part of the earth & glassie hath mastry on the Page [unnumbered] water, and the foresayde rolde hath the victory & mastry. And so S. Gregory his reason is true, yt saith, that Christall may be gendered of water.