Chap. 23-1 SAHDONTT. 417 



points, presenting themselves to the eve. There is no stone 

 llmt IB imitated by fraudulent dealers with more exactness than 

 this, in glass, the only mode of detecting the imposition being 

 by the light of the sun. For when a false' 1 opal is held between 

 the finger and thumb, and exposed to the rays of that luminary, 

 it presents but one and the same transparent colour throughout, 

 limited to the body of the stone: whereas the genuine opal 

 offers various refulgent tints in succession, and reflects no\v 

 one hue and now another, as it sheds its luminous brilliancy 

 upon the fingers. 



This stone, in consequence of its extraordinary beauty, has 

 been called " psederos""' 2 by many authors ; and some who make 

 a distinct species of it, say that it is the same as the stone that in 

 India is called " sangenon." These last-mentioned stonc-s, it 

 is said, are found in Egypt also, Arabia, and, of very inferior 

 quality, in Pontus. Galatia, too, is said to produce them, as 

 also Thasos and Cyprus. The finest in quality of them have 

 all the beauty of opal, but they are of a softer brilliancy, and 

 are mostly rough on the surface. Their colour is a mixture of 

 sky-blue and purple, and the green huts of the smaragdus are 

 wanting : those, too, are preferred, which have their brilliancy 

 deepened by a vinous hue, rut her than those which have their 

 colours diluted, as it were, with water. 



CHAP. 23. SAUDONYX; TIIK SEVERAL VARIETIES OF XT. DEFECTS 



IN TllK SARDONYX. 



Thus far we have spoken in reference to the stones, which, 

 it is generally agreed, belong to the highest rank; in obedience, 

 more particularly, to a decree 73 that has been passed by the 

 ladies to that effect. There is less certainty with respect to 

 those upon which the men as well have been kit to form a 

 judgment; seeing that the value of each stone depends more 

 particularly upon the caprice of the individual and the rivalry 

 that exists in reference thereto ; as, for example, when Claudius 

 Ca?sar was so much in the habit of wearing the sniaragdus and 

 he sardonyx. 74 The first Itonmn who wore a sardonyx, ac- 

 ording to Dernostratus, was .the elder African us, since whose 



71 Tliis is the case with common opal, as distinguished from precious opal. 

 73 " Lovely youth." 



73 Said ironically. There is n somewhat similnr remark in B. xxiiii. 

 . 12.. "* A mixture of brown-red and white chalcedony. 



VOL. VI. JE fl 



