192 <A. A, Hayes—Red Oxide of Zine of New Jersey. 
have stained the white calcite, as a coloring matter would have 
done. This,—with various specimens of my own, including 
part of the most distinctly crystallized form yet found, and 
ranging in color from deep red garnet to reddish-orange—were 
selected as the subjects enabling me to criticise my early results, 
with the light afforded by improved methods of research. To 
those who turn over these pages, it may sum a trivial matter 
whether the color of this mineral be due to “red oxide of man- 
ganese” or another kind of matter, so long as a body foreign 
to the basis oxide of zinc is present. I do not accept this con- 
clusion. . 
h 
The color of the amethyst is due to little flaws and cavities 
filled with a highly refracting coloring matter. This fact 
has been known for about a century. In a quartz crystal 
examined a part of the length was colorless; then a section of 
amethyst was followed by colorless quartz—the summit of the 
was amethyst—and no preceptible disturbance of the 
rocess could be detected. 
