222 G. F. Kunz — Miner alogical Notes. 



Art. XXI. — Mineralogical Notes ; by Geo. F. Kunz. 



1. Phenacite from Maine. 



In May, 1888, some crystals of phenacite were found near 

 Stoneham, Me., in a vein of coarse albitic granite,* associated 

 with crystals of smoky quartz, topaz and muscovite. Some of 

 the crystals were implanted on smoky quartz. A few of them 

 were attached to the matrix by one of the rhombohedral faces 

 so loosely that they could be removed without being broken. 

 They were about thirty in number, lenticular in shape and 

 measured from 3 to 12 mm across, and from 1 to 3 mm in thick- 

 ness. They were all white or colorless, and had polished faces ; 

 the form being for the most part very simple. Figure 1 of 

 the series from Pike's Peak, Colorado, described by Penfield,^ 

 is an exact counterpart of the more highly modified form. 



Of the topaz there were found about a dozen crystals which 

 had unfortunately been broken from the gangue. They were 

 colorless, light-green or cherry colored on the outer sides and 

 colorless in the center. The largest crystal measured 1-J inches 

 in height and thickness. Almost all the crystals contained 

 irregular hollow spaces from 1 to 10 mm across. In habit the 

 crystals closely resemble those from Cheyenne Mountain, Colo- 

 rado. 



It is through the courtesy of Messrs. E. D. Andrews, T. F. 

 Lamb and JST. H. Perry, that I have obtained the crystals and 

 the facts in regard to their occurrence. 



2. Quartz Pseudomorphs after Spodumene. 



In 1887, at the spodumene locality at Peru, Maine, which 

 has furnished tons of that mineral for commercial purposes, 

 there were found some crystals in which the original spodumene 

 had been almost entirely replaced by white quartz, with the 

 exception of a white core of crystallized albite. These crystals 

 are remarkable for the sharpness of the striated prismatic faces ; 

 the terminations are not so distinct. The surface of the crys- 

 tals is covered with a coating of damourite. The alterations 

 of quartz after spodumene are fully described by Julien,^ from 

 the granite veins of Hampshire County. 



3. A remarkable variety of transparent Oligoclase. 



In December, 1887, some specimens of feldspar were sent 

 to me for examination by Mr. Daniel A. Bowman, who ob- 



* This Journal, III, xxvii, 212. \ This Journal, Til, xxxiii, 131. 



X Annals New York Acad. Sciences, vol. i, No. 10. 



