Z48 . DESCRIPTIONS OF MINERALS, 
where. In the United States it is found, in masses, at 
Ilainfield and Cummington, Mass. ; also ‘abundantly at 
Hinsdale, and on Stony Mountain, near Winchester, N. H.; 
at Blue Hill Bay, Me. ‘The black exterior is a more or less 
pure hydrated oxide of manganese. 
Rhodonite may be used in making a violet-colored glass, 
and also for a colored glazing on stoneware. It receives a 
high polish and is sometimes “employed for inlaid work. 
Spodumene. 
Monoclinic. J A J=87, being near the angle of pyroxene. 
Cleavage easy, parallel to 7 and i-i. Surface of cleavage’ 
pearly. Color ee or gr eenish. ‘Translucent to sub- 
translucent. G.=81-3-19. 
Composition. ane Al) OASig tn wine R is hthium and 
equals Li,, and 3 Li, is to Alas 1:4. This corresponds to 
silica 642, alumina 29°4, lthia 6°4=100. B.B. becomes 
white and opaque, fuses, swells up, and imparts to the flame 
tlre purple-red flame of lithia. Unaffected by acids. 
Diff. Resembles somewhat feldspar and scapolite, but 
has a higher specific gravity and a more pearly lustre, and 
affords rhombic. prisms by cleavage. Its lithia reaction is 
its most characteristic test. 
Obs. Occurs in granite at Goshen; also at Chesterfield, 
Norwich and Sterling, Mass. ; at Windham, Me. ; at Brook- 
field, Ct. It is found at Uton, in Sweden ; Sterzing in the 
Tyrol; and at Killiney Bay, near Dublin. 
This mineral is remarkable for the di¢ra it contains, and 
has been used for obtaining this rare éarth. 


Petalite. 
Monoclinic. Usually in imperfectly cleavable masses ; 
most prominent cleavage angle 141° 50". Color white or 
gray, or with pale-reddish or greenish shades. Lustre vit- 
reous to sub-pearlv. Translucent. H.=6-6°5. G.=2°. 
Composition. Contains lithia like spodumene, and gives 
the percentage—Silica 77°9, alumina 17°7, lithia 3:1, ‘soda 
1°3=100. Phosphoresces when gently heated. Fuses with 
difficulty on the edges. Gives the reaction of lithia like 
spodumene. . 
Diff. Its lithia reaction allies it to spodumene, but it 
