380 W. E. Hidden — Mineralogical Notes. 



Art. XL. — Mineralogical Notes;* by W. Earl Hidden. 



Xenotime, from New York City. — In 1872 I discovered, in 

 the vicinity of 155th street and 11th avenue, a single crystal of a 

 mineral which I then determined to be xenotime. It occurred 

 in a coarse pegmatite vein traversing gneiss and associated with 

 much muscovite, tourmaline, brthoclase, quartz and apatite. 

 The determination was based upon the form and physical 

 characters which agreed with those of xenotime. This crystal 

 was T 3 T inch in diameter. It showed the planes 1 (111) and / 

 (110) and in habit resembled figure 438 of Dana's System of 

 Mineralogy. The planes were too uneven to allow of exact 

 measurement. 



In February of this year my attention was called, by Mr. 

 William Mven, of New York, to a series of specimens he had 

 lately collected in the same neighborhood. They included 

 besides black tourmaline, dark green apatite, muscovite and 

 orthoclase, two small brown crystals on separate specimens 

 resembling zircon in form. An indication of prismatic cleavage 

 and the inferior hardness (about 5) led me to believe them to 

 be xenotime ; this determination was confirmed by a chemical 

 test of one of the crystals which yielded a large amount of 

 P a 6 . These new crystals have long prisms and very smooth 

 planes, thus differing from the first one found in 1872. The 

 color is dark hair-brown. It is similar in form to a crystal 

 from Schuttenhofenf figured by H. Sharizer, excepting that it 

 is much longer vertically. It is similar also to the xenotimes 

 from Alexander County already described in this Journal;); and 

 to crystals from Hittero, Norway lately described by Gr. Flink.§ 

 Careful measurements were made by Mr. H. S. Washington, 

 with a Fuess horizontal goniometer, of the angles of one of 

 these New York Island xenotimes. He states that, " the images 

 were very good and the angles are quite reliable and useful for 

 comparison. They agree well with vom Rath's values."! The 

 following were the best angles (supplement) obtained. 



8 /v s (111 * 111) = 55° 32' 30" 



s * r (111 xv 311) = 29° 50' 30" 



giving c: a = 0-619431 : 1 



Only three planes were observed, i. e., s (111), m (110) and 

 r (311). 



* Continued from vol. xxxiii, p. 501. 



f " Zeitschrift fur Krystallographie, etc.." xiii, 1, 1887, figure 1. 



% This Jour., III. xxxii, p. 206, Sept., 1886. 



§ Bihang till K.-Svensk. Vet. Akad. Hand., xii, part 2, No. 2, p. 41 (1886). 



| Jahrb. Min.. 1879, p. 536. 



