Chap. 10.] LUXUET IN THE USE OF CBTSTAL. 395 



there is crystal, but that found upon the Alpine heights in 

 Europe is, in general, more highly valued. According to 

 Juba, there is crystal in a certain island of the Eed Sea, oppo- 

 site the coast of Arabia, called "Necron ;"^^ as, also, in ano- 

 ther neighbouring island^^ which produces the precious stone 

 known as the *' topazus ;" where a block of crystal was ex- 

 tracted, he says, by Pythagoras, the prsefect of King Ptole- 

 mseus, no less than a cubit in length. 



Cornelius Bocchus informs us that in Lusitania, there have 

 been blocks of crystal found, of extraordinary weight, in sinking 

 shafts in the Ammiensian^ mountains there, to a water-level 

 for the supply of wells. It is a marvellous fact, stated by Xeno- 

 crates of Ephesus, that in Asia and in the Isle of Cyprus, 

 crystal is turned up by the plough ; it having been the general 

 belief that it is never to be found in terreous soils, and only 

 in rocky localities. That is much more probable which the 

 same Xenocrates tells us, when he says that the mountain 

 streams often bring down with them fragments of crystal. 

 Sudines says, that crystal is only to be found in localities that 

 face the south, a thing that is known to be really the fact : 

 indeed, it is never found in humid spots, however cold the 

 climate may be, even though the rivers there freeze to the very 

 bottom. Eain-water and pure snow are absolutely necessary 

 for its formation,^ and hence it is, that it is unable to endure 

 heat, being solely employed for holding liquids that are taken 

 cold. From the circumstance of its being hexagonaP^ and 

 hexahedral, it is not easy to penetrate this substance ; and the 

 more so, as the pyramidal terminations do not always have 

 the same appearance. The polish on its faces is so exquisite, 

 that no art can possibly equal it. 



CHAP. 10. LUXURY DISPLATED IN THE USE OF CETSTAL. EEME- 



DIES DERIVED FROM CRYSTAL. 



The largest block of crystal that has ever been beheld by 



53 The Island " of the dead." Brotero supposes it to be the island of 

 Maceira. 



^* See B. vi. c. 34. As Ajasson remarks, there could be no snow or ice 

 here. ^5 gee B. iv. c. 35. 



*^ Dioscorides attributes the hardening of crystal to the action of the sun. 



5'^ "Its shape is rhombohedral, and hemihedral in some of its modifica- 

 tions. The planes on the angles between the prism and pyramidal termi- 

 nations, incline sometimes to the right, and sometimes to the left, and the 

 crystal are termed right and left-huuded crystals." — Dana, SysUm of 

 Mineralogy, Art. Qtcariz. 



