﻿206 W. E. Hidden — Contributions to Mineralogy. 



gave 149° as the approximate angle. R on R adj. = 103°. 

 Occurring with them were some few quartz crystals of remark- 

 able form. Three of the most perfect presented only an upper 

 trapezohedron ( — }f--yf ?) in the termination, the unit rhom- 

 bohedron not appearing even in traces. Others were hemi- 

 morphic, having several acute rhombohedrons (2, 3, 6 and 10RT) 

 at one extremity, and only R at the other. 



Xenotime. — Some few beautiful crystals of this rare species 

 were discovered in the early part of last year at a locality situ- 

 ated about three miles east of the Emerald and Hiddenite Mine, 

 in Alexander Co., N. C. These were found among quartz 

 crystals, considerable rutile in the form of fine yellow needles 

 matted together and some remarkable crystals of monazite 

 (see .p. 207). Only about one dozen crystals were found and 

 these were discovered by washing carefully the whole of the 

 pocket material. The color of the crystals is hair-brown, 

 and some of them are perfectly transparent. Specific gravity 

 =4*45— 4*52. Cleavage prismatic, easy. Habit long prismatic, 

 and in this particular differing from other American xenotimes. 



My own measurements with a Fuess reflective goniometer 

 gave as a mean of many determinations of the angle 1^1 131° 

 14'; the measurements' varied from 131° 9' — 131° 19'. Upon 

 these crystals I identified with a hand goniometer the planes : 

 I, 3, 1, 3-3 and in traces. Of these the plane 3 is new to the 

 species, while 3-3 has been observed by Brezina, and later by 

 Hessenberg, Klein and Brogger. The habit of the North Caro- 

 lina crystal is very closely similar to that of a Swiss crystal 

 figured by Klein ;* they are well represented by figs. 251, 252 

 of zircon in Dana's System of Mineralogy. 



A few of the crystals were sent to Professor Des Cloizeaux, 

 and of them he says : 



" Notwithstanding the beautiful appearance of these crystals 

 of xenotime, they present no faces sharp enough to furnish pre- 

 cise measurement of angles ; which is to be regretted, as all angles 

 published until now are alike uncertain. They oscillate between 

 those of Dana and those of Brogger taken on crystals from Nor- 

 way (G-eol. For. Forh., Stockholm, Dec, 1883). The following 

 are my angles : 



b l &£=(1„3)=152 Q 25'-35'; & 1 m=(l a 7)=131° 15'-45'; bi m=(3^i) 

 =159° 10'— 30'; &£ a 2 =(3/s3-3)=155°approx.; &i &iovera 2 =(3 ^ 3 over3-3) 

 =97° approx.; &' & 1 =(1 ^ 1 adj.) 124° approx. 



Brogger skives 1^7=131° 31', 1^1 adj. 124° 6'. Dana's angles 

 0/0=138° 45', 1^1=131° 15'." 



The smallest crystal measures 3 mm square and 5 mm long, while 

 the largest was nearly 20 rnm long and 10 mm thick. One trans- 



* Jahrb. Min., 1879, 536. 



