F. Pisani on Shepard's Paracolumbite. 359 : 
Art. XXXII.—On Shepard’s Paracolumbite; by Mr. F. Pisani 
of -Patiad::5.:: 
PROFESSOR SHEPARD has given the name Paracolumbite to 
a black mineral found in small grains, or irregular seams, in the 
study its chemical composition. I have thus ascertained, that 
the paracolumbite is nothing more than a titaniferous iron, mixe 
with a little gangue, from which it is extremely difficult to sepa- 
rate it entirely by mechanical means. The mineral occurs in 
lack granules that on pulverization give an equally black pow- 
der. Hardness 45. Density 4:353. Before the blowpipe fuses 
toa black magnetic globule. Partially attacked by chlorhydrie 
acid, and this solution heated with tin gives a violet color. En- 
tirely decomposed by prolonged heat with concentrated sul- 
phuric acid; the addition of cold water gives a solution which 
on boiling becomes cloudy with deposition of titanic acid. 
Shepard,’ on the contrary, states the solution obtained by decom- 
position with sulphuric acid is not rendered milky by boiling, 
and that the metallic acid contained in paracolumbite is not 
Utanic acid. 
A quantitative analysis made by attacking the substance 
with bi-sulphate of potash gave the following results: 
Titanic acid, - : : 35°66 
Ferrous oxyd, - - - - - $908 
Ferric oxyd, - . P> * - 8°48 
Silica and insoluble, - - - - 1066 
Alumina, u ‘ Z : ¢ 7-66 
Lime, % z : & 3 
Magnesia, A s . . - 1:94 
100°54 
Deducting from the analysis the silica, alumina and lime 
Which belong to the gangue, it is obvious that the mineral is an 
rdinary titanic iron, Paracolumbite cannot therefore be con- 
Sidered’a distinct mineral species. It is identical with titanic iron, 
* Communicated by the author. * Mineralogy, 2d edition, (1857,) page 287, 
Paris, (France,) Feb. 4th, 1864. 
