S2 NEW YORK STATE MUSEUM 



matrix is performed by mechanical methods. After the rock is 

 blasted in the quarry, it is loaded by means of a steam shovel into 

 cars and is then transported to the mill, which is situated on the 

 hillside below the quarry. The rock is there broken and crushed to 

 a size which releases the garnet particles and then goes to jigs of 

 special design. These effect a separation of the garnet and the 

 accompan3dng gangue minerals of which hornblende and feldspar 

 are the principal representatives. Inasmuch as the garnet and 

 hornblende vary in specific gravity by less than one-half of a unit, 

 careful work must be done to produce a garnet concentrate that is 

 measurably free from foreign admixture, but the separation is per- 

 formed successfully. The garnet from this locaHty has a darker 

 color than that from the other mines now under operation and can 

 be readily distinguished by that feature. 



At the Gore mountain locality the gametiferous material is con- 

 fined to a long narrow band which possibly represents an altered 

 dike of gabbro or an inclusion of Grenville gneiss in the country 

 syenite, since it consists largely of hornblende and stands out prom- 

 inently from the surrounding rock. The deposit is of much' more 

 limited extent than that at Thirteenth lake, but on the other hand 

 contains a much higher percentage of garnet. This mineral occurs 

 in rounded masses and aggregates, some of which attain great size, 

 that is,. 2 or 3 feet in diameter, and weights of a thousand pounds 

 or more. The garnet masses are really crystals that have been 

 subjected to powerful compressive strains which have resulted in 

 its fracture into small angular particles, and when a mass is exposed 

 in the quarry the garnet can be readily extracted by hand picking 

 which is the method employed. The garnet from this locality, as 

 well as that from Thirteenth lake, when crushed always yields one 

 or more smooth surfaces which represent the parting planes charac- 

 teristic of crystallized garnet. 



In the occurrence near Wevertown the garnet is found in some- 

 what different association than that described. It consists of a 

 light red garnet of granular habit intergrown or intermixed with 

 green pyroxene, the two minerals together constituting the rock 

 mass. In places the garnet may occur practically pure so as to 

 form larger or smaller bodies by itself. When broken it rarely 

 exhibits the parting, but shows a granular habit, the particles having 

 irregular boundaries. A similar occurrence was worked for a while 

 in northern Essex county near Keeseville, and there the garnet- 

 pyroxene rock was clearly the result of contact metamorphic influ- 

 ences upon Grenville limestone. A small product has been obtained 



