340 J. D. Dana on some points in Lathology. 
The word Gabbro, as it is now used (and was so first by von 
Buch in 1810) is applied to the granitone, the associate of the 
Italian gabbro; but, besides this, to rocks consisting of foliated 
pyroxene (sometimes called hypersthenite), and cleavable lab- 
radorite the idea of foliated standing out prominently ; and also 
to an eruptive diabase-like or doleryte-like rock, in which the 
augite happens to be foliated. 
n this last variety, as the analyses show, there is evidently 
no foundation whatever for separating the rock from other 
labradorite-augite eruptive rocks. 
Granitone is the same as euphotide, a rock distributed at 
intervals along the Alps from Savoy and Isére in France 
through Piedmont, to the valley of the Saas, north of east of 
Monte Rosa, and the Graubiindten, occurring also in Silesia and 
on the island of Corsica, and found commonly associated with 
serpentine. Its chief characteristic is—not its foliated diallage 
or smaragdite (either of which is usually a mixture of horn- 
blende and pyroxene), but its consisting largely of the com- 
pact jade-like material called saussurite ; for it would be the | 
- rock, essentially, whether the hornblende and pyroxene | 
were distinctly foliated or not; and, in fact, in part of it the | 
texture is aphanitic, and nothing foliated is distinguishable. | 
Saussurite has a close relation to some of the feldspars in its | 
constituents, it being essentially a soda-lime-alumina silicate ; | 
and still, as has long been recognized, it is not afeldspar. This 
has been rightly sustained by the fact of the high density, 
which is over 2°9 (2°9 to 8-4), in saussurite, and less than 2°765 
in the feldspar group. It is further proved by its occurrence 
occasionally under the crystalline forms of a triclinic feldspar, 
but with a fine granular or aphanitic structure; thus having, 
instead of the cleavage structure belonging to the feldspar, a 
feature belonging to a pseudomorph. In such cases it was once 
feldspar; but some change has come over it that has resulted 
in a molecular transformation, affecting both the crystalline 
character and the density. Saussurite appears to cover a group 
of minerals, like feldspar. One kind is between anorthite and 
zoisite in composition, though differing from both in the soda 
a 
sauss 
peamien with the feldspar group. The first is Saussurite, Th 
