Obap. 37.] lASPis. 431 



which only emhraces the margins of the stone, leaving the 

 upper and lower surfaces uncovered, One great defect in 

 them is a subdued lustre, and a want of refulgence when 

 viewed from a distance. Grains also like salt appear within the 

 stone, and all the other defects which are common^"' to precious 

 stones in general. Sometimes they are imitated in glass ; a fraud, 

 however, which may be easily detected, from the material 

 throwing out its refulgence, instead of concentrating it within 

 itself. To this class also belongs the stone called *' sphragis,""^ 

 which is only reckoned as belonging to the domain of precious 

 stones, from the circumstance that it is the best of all for 

 making signets.*' 



(9.) Throughout all the East, it is the custom, it is said, to 

 wear iaspis by way of amulet. The variety of this stone 

 which resembles smaragdus in colour is often found with a 

 white line running transversely through the middle ; in which 

 case it is known as *' mouogrammos :"^" when it is streaked 

 with several lines, it is called " poly gram mos."^^ Here, too, I 

 may take the opportunity of exposing the falsehoods®'^ of the 

 magicians, who pretend that this stone is beneficial for persous 

 when speaking in public. There is a stone also that is formed of 

 iaspis and onyx combined, and is known as " iasponyx."^^ Some- 

 times this stone has a clouded appearance ; sometimes it has 

 spots upon the surface like snow f'^ and sometimes it is stel- 

 lated with red spots. ^^ One kind resembles salt of Megara^^ in 

 appearance, and another is known as capnias,^^ and looks as if 

 it had been smoked. We have seen in our day an iaspis^ 



5- See Chapter 18 of this Book. 



5^ *' Seal stone." A kind of carnelian, probahly. 



59 " Publico gemmarum doininio iis tantura dato, quoniam optime sig- 

 nent." The above is the sense given to the passage by Holland, Ajasson, 

 and Littre ; bat another translation may also be suggested— "A stone to 

 which alone, by general consent, is awarded the custody of precious stones, 

 from the fact that it makes the best impression as a seal.'' In reference 

 to the custom of putting a seal on the dactyliothecse, or jewel-caskets. See 

 page 80 of this Book. 



^^0 "Single-lined." ®^ "Many-lined." 



^ Albertus Magnus, De Mineral. B. ii., has several other stories res- 

 pecting it of a similar nature. ^^ Jasper onyx,. 



«* Identified by Ajasson with snow-flake chalcedony. 



65 Spotted jasper onyx. ^^ See B. xxxi. c. 41. 



6'J Smoked jasper onyx. 



68 It is still used for making vases, boxes, knife-handles, and other arti- 

 cles, and ia much used in the manufacture of Florentine mosaics. We 



