Hidden and Pratt — Associated Minerals of Rhodolite. 463 



Art. XLYII. — On the Associated, Minerals of Rhodolite / by 

 W. E. Hidden and J. H. Pratt. 



In a recent paper on rhodolite, a new variety of garnet,* 

 the authors gave a list of the associated minerals, and it is the 

 purpose of this article to describe them more fully. All the 

 minerals have been obtained from the gravel beds of Mason 

 Branch, which empties into the Little Tennessee River about 

 five and one-half miles below Franklin, the county seat of 

 Macon County, North Caroliua. These gravel beds have been 

 mined quite extensively for rhodolite by means of hydraulic 

 processes and the species herein described have been found 

 wholly in the concentrates. When the minerals shall have 

 been traced to their source, as they promise to be soon and 

 mining in situ inaugurated here, this locality may be expected 

 to become one of unusual interest to mineralogists and geol- 

 ogists. 



Quartz. — Compact crystalline and granular quartz is abund- 

 ant as rolled pebbles and rounded bowlders (rarely weighing 

 above 20 kg.). Crystals are occasionally found but are of very 

 ordinary character. Massive quartz enclosing rhodolite and 

 iolite, often both in the same mass, are not uncommon. 



Quartz pseudomorphs. — An important characteristic of the 

 locality is the occurrence of quartz pseudomorphs in the form 

 of isometric dodecahedrons, bearing upon their faces markings 

 exactly like those seen upon garnets. These crystals, some- 

 times l cm diameter, are wholly perfect and are rarely irregularly 

 grouped together. They are gray in color and apparently 

 homogeneous, with the exception of numerous inclusions of 

 minute red rutile and black menaccanite. Their density, 

 determined upon a single typical specimen, was 3*203, which 

 was low for garnet and high for quartz. When pulverized and 

 treated with the heavy solution to separate out the rutile and 

 menaccanite, the remaining material was found to be a mix- 

 ture of colorless quartz and the rhodolite variety of garnet. 



The manner of their original formation and what was the 

 original dodecahedral mineral, offer peculiar problems, for the 

 crystals are undoubtedly not ordinary pseudomorphs. They 

 never show any projecting neck or rough broken surfaces such 

 as would indicate a pre-existent cavity through which this 

 material might have passed into a cavernous garnet. It is our 

 intention to study sections of these crystals, to determine if 

 possible, the relation of the quartz and garnet in them, whether 

 there are parallel layers of these minerals or whether the optic 



* This Journal, vol. v, p. 29J, 1898. 



