Mineralogy and Geology. 267 
tween apple and grass green. It occurs in incrustations of small 
accretionary cylindrical stems. * f 
5. Crystalline form of Geocronite ; (Poggend. Annalen, lxv, 302, 
1845.)—Crystals of Geocronite, from the Val di Costello, have an ob- 
lique rhombic primary, the lateral angle of which is 153°. They occur 
under the form of a six-sided prism, terminated in four-sided pyramids ; 
one of the angles of the pyramid is 122°. The composition determined 
by T. Kerndt, is very similar to that obtained by Svanberg. 
6. Piauzite,a new mineral ; (L’Institut, Nov. 1845, No, 619, p.400.)— 
M. Haipinekr has detected a new resin near Neustadt, at Piauze. It 
is compact, with a slightly conchoidal fracture, brownish black color, 
and feebly translucent on the edges. Its density is 1-220, and it fuses 
at 515° C., burning with a brilliant flame, and a slightly aromatic odor. 
It dissolves completely in ether and a solution of caustic potash, and 
also almost entirely in absolute alcohol. 
7. Dysclasite—The primary form of the crystals of this mineral, as 
determined by Breithaupt, is a right rhombic prism of 122° 19’, 
This mineral has been lately found abundantly, in a massive state, at 
Copper Harbor, Lake Superior. 
8. Columbite and Wolfram; (Pogg. Annalen, Ixiv, 171, 1845.)— 
G. Ross, in his investigations of these minerals, has detected a 
close similarity in the forms and angles of their crystals, showing that 
they belong to the same system, and are approximately isomorphous. 
Three angles in Columbite have the values 100° 40’, 97° 29’, and 
93° 16’, and the corresponding in Wolfram are 101° 5/, 99° 12’, 91° 
54’. The cleavage is similar in direction in the two minerals, but is 
more perfect in Wolfram. The facts indicate that oxyd of niobium, 
which is contained in the Columbite, is isomorphous with oxyd of tung- 
sten. 
9. Trichroism of Crystals ; (Poggend. Annalen, Ixv, 1, 1845.)— 
M. Harprnee, in an elaborate memoir on the pleochroism of crystals, 
after describing at length instances of dichroism, and their peculiarities, 
enters into a consideration of the transmitted colors of crystals with 
three unequal axes, which he shows to afford instances of trichroism, 
The colors are observed either in the line of the axes, or perpendicular 
to the faces, and often appear different in six directions. Iolite, though 
called dichroite, is an example of this trichroism. 
10. Phosphorescence of the Diamond.—P. Rigss, experimenting on 
the phosphorescence of a large number of diamonds, found that in many 
of them, an exposure of half a minute to the sun’s rays, caused them 
to give out light for fifteen to twenty minutes, on being removed into 
the dark. The phosphorescence produced by the red rays, continued 
longer than that from any other of the colors, | 
