140 CONTRIBUTIONS TO MINERALOGY. [bull. 2& 
several centimeters in diameter. At Auburn, Me., several specimens o 
globular lepidolite were found in the summer of 1904 by Mr. Wade 
working on Pulcifer's ledge on Mount Apatite. Some of these wer 
fairly large, one such specimen (by no means the largest) collected b 
the writer being 6 cm. in diameter and 2£ cm. thick. Here, at Moun 
Apatite, this globular form of lepidolite is abundant and forms one o 
its characteristic phases. It often has a whitish border (a few milli 
meters thick) of some undetermined mineral (probably a mica) sur 
rounding it. 
20. LIBETHENITE. 
Some minute crystals of libethenite, about a millimeter in diameter 
from Yerington, Lyon County, Nev., proved to be weil adapted fo 
measurement. As the symmetry of the mineral has been regarded a, - 
orthorhombic by some writers and monoclinic by others, it was hope< 
that the measurement of these crystals might contribute something t< 
the question. The results have been very satisfactory and show tha 
the crystals measured are orthorhombic and not monoclinic. 
The crystals were collected by Mr. D. Smith, to whom the writer | 
under obligations for the material investigated. Qualitative chemicai 
tests showed the presence of copper, phosphoric acid, and water: 
Some time after these measurements were made an article by Meld 
zer a appeared on the symmetry and form of libethenite, in which h« 
came to the same conclusion as the writer in regard to the symmetrl 
of the mineral, his conclusion being based on a large number of meas 
urements of Cornwall crystals. There can therefore hardly be an! 
more question as to the orthorhombic character of libethenite. 
The crystals measured are minute, less than a millimeter in diam 
eter, but well formed, and the faces usually give very good and shall 
signals. As the unit prism is present on all crystals, they were easil 
adjusted in true polar position and could be quickly and accurateH 
measured with the two-circle goniometer. 
Under the microscope the crystals always extinguish parallel to the 
crystallographic axes. No phenomena, such as twinning structure oi 
twinning lamella?, could be observed, either under the microscope or 
on the goniometer. 
Seven of the most perfect crystals were removed from the matrix 
and measured. The forms observed are : h = {010}, m = {110}, * h — {olO}, 
#={310}, */={ll0}, £={011}, #={101}, {*=111}. 
« Melczer, G., Ueber Libethenite: Zeit. f. Kryst., vol. 39, 1904, p. 288. 
