Auriferous Districts of Wicklow. 83 



second variety of garnet, from which it is readily distin- 

 guished by its peculiar purplish-red colour. 



Gold. — This mineral occurs here in probably its most 

 beautiful form. It possesses the true golden yellow colour 

 and metallic lustre which characterise the metal, and, owing 

 to the attrition to which it has been subjected, generally 

 presents a beautifully brilliant surface. It occurs in grains 

 of all sizes, from the smallest spangle up to a mass weighing 

 22 ounces, the largest hitherto found. The specific gravity 

 of some small grains Mr Mallet found to be 16*342. The 

 analysis of these grains gave — 



Gold, .... 



Silver, .... 



Iron, .... 



99-27 



This is equivalent (neglecting the iron) to 8^ atoms of gold 

 and 1 of silver. 



Flatina, — Mixed with the gold are some very small flat- 

 tened grains of a white colour and metallic lustre, which, as 

 far as their minute size permitted an examination, appear to 

 present all the characters of platina. They are infusible 

 before the blowpipe, and insoluble in nitric acid, but dissolve 

 in aqua regia. Their occurrence, intermixed with the gold 

 when all other minerals have been washed off, is a proof of 

 their high specific gravity.* 



Tinstone. — The occurrence of this mineral in the sand is 

 mentioned by Weaver in his reports on the gold-stream 

 works, but he does not seem to have been at all aware of 

 the large quantities in which it exists. From the compara- 

 tively small portion! of sand which the author had an oppor- 

 tunity of examining, he obtained about 3J pounds of stream 

 tin ; a portion of which being reduced, yielded an ingot, 

 which, when refined by a. second fusion, is hardly inferior 



♦ It is to be wished that the existence of platina had been more fully ascer- 

 tained.— j;d. Phil. Mag. 



t The exact weight of the specimen examined, the author does not know, 

 but thinks it certainly did not exceed 150 lbs. 



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