CRYSTALLOGRAPHICAL EXAMINATIONS. 
509 
An ore of cerium, called allanite, occurs in several localities in Phillipstown and Cornwall, 
within two miles of Fort Montgomery, and it is thought other ores of this metal were observed 
some years ago. One of them was partially examined, and reagents showed some of the traits 
of that metal. 
IV. CRYSTALLOGRAHPICAL EXAMINATION OP SOME MINERALS. 
1. CRYSTALLIZED SERPENTINE. 
Serpentine was found crystallized at Hustis’s quarry in Phillipstown, Putnam county, first 
by Dr. Barratt in 1821, and secondly by Cadet Ward, November 5th, 1831. As by means 
of crystals from this locality I have been enabled to ascertain the primary form and its ele¬ 
ments, I will state the facts and investigations as they occurred, from my diary. 
November 5, 1831. On an excursion to-day, with the first section of my class in mineralogy, 
to Hustis’s quarry. Cadet Ward handed me a specimen of serpentine for examination. I 
immediately observed traces of crystallization, there being numerous well characterized laminae, 
and showing tolerably brilliant cleavage planes also in other directions. 
November 1, 1831. I have succeeded to-day in determining imperfectly the angles of the 
primary form, but the faces are not sufficiently brilliant to give a perfect reflected image with 
the reflective goniometer. The measurements seem to indicate a doubly oblique prism, and 
there is a distinct cleavage also parallel to the shorter diagonals of the faces T and T'. 
Fig. 26. 
P on m ... 
P 00 . m' _ 
P onT ... 
P on T'... 
Tw on T_ 
m oxiT' _ 
P on/ ... 
90026 ' 
80 34 
95 20 
84 40 
92 00 
88 00 
128 00 to 128030' 
From these measurements, it appears to 
be a doubly oblique prism of 
P on m_ 90026' 
P on T ... 95 20 
TO on T_ 92 00 
The ratios of the edges cannot be determined, until crystals having planes modifying the 
primary edges shall be found and measured. Much of the serpentine in some parts of the 
hill-side at Hustis’s quarry is granular, and some is laminated. Cadet Bailey, now Professor 
Bailey at West-Point, and who was one of the section of the mineralogical class, also presented 
me with a specimen of crystallized serpentine imbedded in carbonate of lime. There were 
several hexagonal crystals terminated, one of which was nearly perfect. The crystals and 
crystalline masses are more perfect than any I have seen from the Easton locality, and Dr. 
Swift was so kind as to send me some of the best specimens of that locality. 
