262 DESCRIPTIONS OF MINERALS. 
boldtilite) is a related dimetric species, from Capo di Bove, 
near Rome, and Mount Somma, Vesuvius. 
Epidote. 
Monoclinic. 7-¢A1 7=115° 24°. 1-1A —1-1=116° 18. =1 7K 
—1=109° 35’. Cleavage parallel to 
ERI, 1-4; less distinct parallel to 1-2. 
Also massive granular and forming 
rock masses ; “sometimes columnar 
or fibrous. 
Color yellowish green (pistachio- 
green) and ash-gray or hair-brown. Streak uncolored. 
Translucent to opaque. Lustre vitreous, a httle pearly 
on 1-2; often brilhant on the faces of crystals. Brittle. H. 
=f, G.=3 '25-3'5. 
Composition. A lime iron-alumina silicate, the 1 iron being 
mostly in the sesquioxide state and replacing ‘aluminum. 
Percentage of common variety, Silica 37°83, alumina 22°63, 
iron sesquioxide 15-02, iron protoxide 0°93, hme 23°27, 
water 2°:05=100°73. 
B.B. epidote fuses with effervescence to a black glass 
which usually is magnetic. Partially decomposed by. hy- 
drochlorie acid, but “ft first ignited, is then decomposed, 
and the solution gelatinizes on “evaporation. 
Green epidote is often called Pistacite. Piedmontite is 
a variety containing much manganese, of reddish-brown or 
reddish-black color. 
Bucklandite is an ivon-epidote. 
Diff. Vhe peculiar yellowish-green color of ordinary epi-_ 
dote distinguishes it at once. From zoisite and vesuyian- 
ite it differs in fusing to a black magnetic globule. 
Obs. Occurs in erystalline rocks, especially in hornblen- 
dic rocks. It often occurs in the cavities of amygdaloidal 
rocks. Splendid crystals, six inches long, and with bril- 
liant faces and rich color, have been obtained at Haddam, 
Ct. Crystallized specimens are also found at Franconia, 
N. H., Hadlyme, Chester, Newbury and Athol, Mass.; 
near Unity, Amity, and Monroe, N. Y.; Franklin and 
Warwick, N. J.; Pennsylvania, at E. Bradford ; Michigan, 
in the Lake Superior region ; Canada, at St. Joseph. 
The name epidote was derived by Hatty from the Greck 
epididomi, to increase, in allusion to the fact that the base 
of the primary is frequently much enlarged in the crystals. 

