1832.] Precious Minerals. 361 



barjad. This may be easily accounted for by the similarity of 

 their prismatic crystallization : beryl or aquamarine, a variety of 

 emerald, passes from green into a yellow color; and the striated 

 prisms of topaz pass from a deep golden yellow to a pale green 

 color. Their difference in specific gravity and chemical compo- 

 sition could not be known to a lapidary ; their hardness is nearly the 

 same, and they occur in the same mines in Egypt and elseAvhere : 

 indeed the term beryl was applied to both by Werner. The aqua 

 marina or beryl is called beruj : specimens shewn me had a specific 

 gravity 2.70. The Indian name for topaz is piikhraj, whence has been 

 taken the modern Arabic appellation of topaz, buszdk. 



The Turquois. 



p. Jirozeh* ; g. naWais ; s. peroj P 



The name Firozeh is said in the Jawdhir-nameh to have been 

 given to this stone by Firoz Shah, but this must be matter of doubt ; 

 as also whether the Sanskrit synonyme in Hunter's Dictionary, peroj, is 

 not a corruption of beriij, beryl, quite a different stone. From the loca- 

 lities and from the characteristics of the two varieties in the books 

 before us, it might be conjectured, that the two species of this mi- 

 neral known to European mineralogists, as the calaite, or mineral tur- 

 quois, and the odontolite, or bone turquois, are equally familiar to the 

 Persian jewellers, under the epithets of Abu-Isliaqi and Badakshani. 



The Aba-Isliaqi, (father of Isaac,) or genuine turquois, is the pro- 

 duce of the mines of Ansar, near Nishapdr^ in Khorasan, (the same 

 place mentioned as Michebourg, in Tavernier's Travels in India.) All 

 authorities concur, that these are the only turquois mines in the world : 

 the stones are said to vary from pale blue to green and white, but all ex- 

 cept the azure are worthless. A curious fact is mentioned also, which, from 

 the nature of the mineraR may be readily believed, though it has not 

 been observed in Europe : " the real blue turquois of Nishapur changes 

 its color when kept near musk or camphor, also from the dampness 

 of the ground, as well as from exposure to the firej ; the inferior 

 stones become discolored even without this test," by gradual decompo- 

 sition or efflorescence. The Khawds-ul-hejdr makes the clearness or 

 dulness of the turquois vary according to the atmospheric changes. " It 

 brightens the eyes ; is a remedy for ophthalmia and bites of venomous 

 animals ; it is used in enamelling sword handles, &c." 



* Firozeh nakis, an inferior turquois, is enumerated amongst the mineral pro- 

 ducts of Tibet, by Abdul Kadir Khan, in the History of Cashmir before quoted. 



f Vide Gleanings in Science, II. 375. 



I Pliny also remarks of the Callais ,■ " quae sunt earum pulchriores, oleo, un- 

 guento et mero colorein deperdunt." 



z2 



