TioHBORNB — Oil an Argentiferous Galenetic-hlende. 301 



trict called Kilmacoo. It is so called in Mr. Argall's Paper. THe 

 mineral seemed to have been well known to Mr. Gr. H. KinaLan, 

 whose intimate knowledge of the mineralogy of county Wicklow 

 induced me to make inquiries of him. He gives as localities — the 

 lode of the Magpie mine and the Connary mine, both in East 

 Ovoca, with the Mona mine in Anglesey. 



It is called " Bluestone" by the mining inspectors,^ and it seems 

 that about 1,240 tons of this or a similar ore are raised in the prin- 

 cipality during the year. 



The ore is a hard, steel-grey-ooloured mineral, having something 

 of the appearance of sulphide of antimony. If we except the colour, 

 however, it does not resemble that mineral in any respect, for the 

 structure is that of a fine-grained sacchorid mass. The ore is 

 extremely hard, and it is broken with difficulty. In fact the rock 

 has to be quarried by blasting. The pieces I have seen are very 

 uniform in character, but are occasionally interspersed with crystals 

 of pyrites and a hard, black, siliceous rock. A very slight exami- 

 nation will suffice to determine the fact that this mineral is a natural 

 lode, and is not the result of an ancient working. This latter theory 

 was once upon a time promulgated. 



A piece weighed in the air 34 '9 42 grammes : when weighed in 

 water it gave 27"5655 grammes as the weight, so that the mineral 

 has a specific gravity of 4*786. It will be observed that this gravity 

 is somewhere intermediate between galena and blende. It is harder 

 than either of those minerals. The ore, as found in Ovoca, seems, 

 from the description given of the Welsh mineral, very much of the 

 same character. But I have never seen a specimen from the Mona 

 mine. As will be perceived further on, however it differs in 

 general composition, it is much richer in silver than one of the 

 varieties found in Wales. To quote from the Mineral Statistics, 

 we are told that " Bluestone is an ore of zinc ; average analysis — 

 zinc, 32*15 per cent.; lead, 11'6, and lOf ounces of silver per ton, 

 with a small percentage of iron and copper." But at page 88 in 

 the same book we are informed that from the Mona mine, in 

 Wales, they extract 5-535 ozs. from 514 tons, and that at the 

 Morfa Du mine 5*082 ozs. from 726 tons, which represents re- 



^ Mineral Statistics of the United Kingdom of Great Britaia and Ireland, for the 

 year 1882, p. 5. 



