JADE. 



the manufacture of implements. The magnificent collection of 

 celts at Dublin has been specially studied, from a mineralogical 

 point of view, by the Kev. S. Haughton, and the results are 

 thus recorded by Wilde :* 



"Of the better qualities of rock suited for celt-making, the 

 type of the felspathic extreme of the series of trap rocks is 

 the pure felstone, or petrosilex, .... of a pale blueish or 

 greyish green, except where the surface has been acted upon, 

 and the average composition of which is 25 parts quartz and 

 75 felspar. Its physical characters are absence of toughness, 

 and the existence of a splintery conchoidal fracture almost as 

 sharp as that of flint ..... At the hornblendic extreme of the 

 trap rocks we find the basalt, of which also celts were made ; 

 tough and heavy, the siliceous varieties having a splintery 

 fracture, but never affording so cutting an edge as the former. 

 .... Intermediate in character between these two rocks, we 

 find all the varieties of felstone, slate, and porphyry streaked 

 with hornblende, from which the great majority of the fore- 

 going implements have been made." 



It is very remarkable how carefully the best kinds of stone 

 were selected, even when very rare. Of this the most interest- 

 ing example is afforded by the axes, etc., of Jade or Nephrite, 

 of Jadeite and of Saussurite. These minerals are very 

 distinct chemically, but so similar in appearance that they 

 can only be distinguished by analysis. Objects made from 

 them, though far from common, are not very rare. M. Fischer 

 gives the following table : 



France. Germany. Switzerland. 



Jade or Nephrite . . 3 1118 



Jadeite ...... 77 46 138 



Chloromelanite ... '53 17 



Till 1884, no European locality of Jade or Nephrite was known, 

 * Catalogue of the Royal Irish Academy, p. 72. 



