928 W. P. Blake on the Chalchihuitl of the Mexicans. 
been carefully collected. A recent heavy shower had, however, 
brought many small pieces of the nine in view on the surface, 
and other specimens were procured by breaking open the rocks. 
The specimens present in color various shades of apple-green 
and pea-green, passing into bluish-green. Some fragments hav- 
ing a blue color were found, but these are not so dense and hard 
as the green. Some of the specimens very closely resemble crusts 
or coatings of chrysocolla both in fracture and color; differing, 
however, very essentially in the hardness. Some of the bluish 
specimens are very soft and earthy, and appear to be the result 
partial decomposition of the green portions by long exposure. 
One of the compact green fragments has been successfully cut 
by a lapidary; it takes a fine polish, and has a pleasing color and 
lustre suitable for jewelry. The hardness is a little less than 
that of feldspar, and the specific gravity varies from 2°426 to 
_ 2°651, the compact, green fragments giving the highest numbers. 
Before the blowpipe, it fuses with intumescence on the thin 
ges only; in other respects, the reactions are similar to those 
of turquois. An analysis of it forme by J. M. Blake of the. 
and iron, colored with oxyd of copper. 
The fragments which were ae gk ad? 
uarters of an inch in length and one quarter of an inch 1 
ickness. They appeared to have caries 
rock are compact and homogeneous, and pi 
closely to the walls on each side. It is therefore difficult 
cases 1t is compact and without any trace of crystalline sro 
: : rs 
Specimens are nearly identical in appearance with the turqu 
from Steine in Silesia, for a fragment of which I am indebted to 
Prof. G. J. Brush. - 
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