336 T. S. Hunt on Euphotide and Saussurite. 
‘ 
Art. XXXVII.— Contributions to the History of Huphotide and 
Saussurite ; by T. SterRyY Hunt, of the Geological Survey — 
of Canada. b 
1. The name of euphotide was originally given by Haiiy 
to a rock composed of diallage and a white compact mineral 
which he designated as feldspath tenace, (the compact feldspar of 
Werner, the lemanite of Delamétherie, and the jade of de Saussure 
senior). The well-marked contrast of colors which suggest 
the name of euphotide is seen in the beautiful verde di 
or verde antico di Orezza, and in some varieties of the rock from 
Mt. Rose. In these the diallage is represented by a grass-greel 
smaragdite, and this mineral and hypersthene pe 
y Haiiy as varieties of diallage, he included under the head of 
euphotide, the verde di Corsica, (for which alone d’Halloy ™ 
tains the name of euphotide,) the hypersthenite or hyperite of 
other authors, and the granitone of the Italians. This last by 
an error of Von Buch, in which he has been followed hee 
Rose, is very frequently called gabbro. The true gabbro of th 
Italians is however a diallagic ophiolite. (Brongniart, Classy 
des Roches, 1827, p. 75. : “th 
Brongniart defines euphotide to be a mixture of or i ; 
jade, petrosilex, or compact feldspar, and including d Halley 
two species, euphotide and granitone, but excluding hype Sa 
he distinguishes as varieties, jadian and feldspathic — “i 
ose. Ye 
Coquand (Traité des Roches, 1857,) has followed Haiiy wit ® 
gard to the euphotides, while Senft (Die Felsarten, 180/,) hat, 
ragdite. The eclogite of Haiiy is composed of diallage hrough 
ragdite, and-red garnet; it often holds disthene (cy anit ofa) 
the predominance of which it passes into disthenite ( Rose) js 8 
while hypersthenite or hyperite (hypersthenfels, G. (a'Hally 
mixture of saussurite or labradorite with hypersthene 
" contsie! 
nft.). 
Distinctions like some of the above based upon the portance 
and it becomes necessary to define with more strictne® ja 7 
ture of the other element of the rocks in question. gave 
of the Swiss Alps to which de Saussure junior, senior, 8 
the name of saussurite, was described by de meee ig | 4 
compact, tenacious, greenish-white in color, i 3-31 389. 
scratch quartz, and having a specific gravity © 7 
