REMARKABLE OCCURRENCE OE AURICHALCITE. 
BY CHARLES R. KEYES. 
Good aurichalcites are among the rarer specimens in 
mineral collections. The peculiar feathery habit of crystal- 
lization makes the mineral difficult to handle and difficult 
to preserve even after being collected. 
Aurichalcite is a basic carbonate of zinc and copper 
having, according to Penfield, a chemical formula which 
should be written 2 (Zn, Cu) Co 3 .8 (Zn, Cu) (OH 2 .) 
The aurichalcite which is here exhibited is from the 
Graphic Zinc Mines in the Magdalena mountains, in central 
New Mexico. The noteworthy feature of the occurrence is 
that the delicate plumose clusters of crystals are preserved 
by clear crystalline calcite. On this account the rarer 
mineral is perfectly preserved and is easily handled with- 
out danger of destruction. 
The single occurrence known in the Graphic mines is of 
indescribable beauty. A crystal grotto ten or a dozen feet 
in diameter is entirely lined with exquisite and delicately 
tinted aurichalcite which is again covered by a thin layer 
of calcite one-quarter to one-half inch in thickness made up 
of very perfectly and brightly faceted crystals closely grown 
together. 
Some of the showiest specimens obtained were four to 
five times the size of a man's head. 
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