378 Reéxamination of American Minerals. 
terial that had been placed in my hands by that gentleman, nearly 
a gramme of the substance has been procured, and upon that the 
followmg examination has been made. 
Some of the crystals are exceedingly short prisms surmounted 
by four-sided pyramids, but most of them are without the prism, 
the summits coming together forming a flattened octahedron. 
‘The measurements made were: over the pyramidal edge 123° 10/, 
over basal 81° 30’, face of pyramid on prism 131° 40’. The 
above measurements can be made with perfect accuracy ; not so 
the faces of the prisms on each other, and as far as I could make 
it out, IT am inclined to think that they are not square prisms, 
but rhombic prisms of 93°. Its hardness is 4°5, sp. gr. 4°54, an 
the physical characters those given for Xenotime. j 
t was decomposed by fusion with carbonate of soda and sil- 
ica, and analysed with the following results : 
Phosphoric acid, . ; : : ; 3 82°45 
Yttria, ; : : g AMG : . 5418 
Oxyd of Cerium, (with a little La and D) b ‘ 11-03: 
Oxyd of iron, . ; _ ' ‘ . 206 
Silica, : : ; : ; : 0°89 
10056 
This analysis will be seen to differ from that of the Xenotime 
of Hitteroe, Sweden, by Berzelius, in that a portion of the yttra 
is replaced by the oxyd of cerium; the formula represented by 
the analysis is, however, the same, namely, 
er -(Y, Ga)s : 
_ Great care was taken in the separation of the oxyd of cerium, 
which after being peroxydized by heat, yielded but little to dilute 
nitric acid, indicative of the presence of but a small quantity of 
the oxyds of lanthanum and didymium. 
42. Lanthanite. eet 
This mineral was first observed in America by Mr. W. P. 
Blake, and described in this Journal, Sept. 1853; it was obtained 
by Mr. Blake from Bethlehem, Lehigh Co., Pa., where only one 
specimen had been found. It was handed to me for examination, 
and ascertained to be carbonate of lanthanum ; the analysis made 
was given in thé original description of the mineral. Since ten 
I have made another analysis on a portion remaining in my pos- 
session, and although not differing from the former one, It 1S 
‘thought proper to insert it in this paper. = mers eee 
é Water, . : : ing s fib toes ga 2409 
*~<Carbonie acid, — . : . r 3 cS BTO6- . ot 
~~ Protoxyd of Lanthanum (with some oxyd of Didymium), 55:03 hil ety 
4 coe iis 
2. Bad 
a ae ea aaa, a ne Be 
