130 S. L. Penfield—Phenacite from Colorado. 
ArT. XV.—Phenacite from Colorado; by SamMuEL L. PEN- 
FIELD. Wdeth notes on the locality of Topaz Butte; by WALTER 
B. SMITH. 
THE occurrence of phenacite in the United States was first 
mentioned by Messrs. Cross and Hillebrand,* who published a 
short description and figure of a crystal occurring with micro- 
cline (amazon stone) from the Pike’s Peak region, El Paso Co., 
Colorado ; later these same authorst gave a more detailed de- 
scription of more complicated crystals from Florissant, in Hl 
Paso Co. At about the same time Mr. W. E. Hidden{ men- 
tioned the occurrence of phenacite from Florissant; a second 
note by him, recently§$ published, contains some crystallo- 
graphic notes and two figures by Prof. Des Cloizeaux, of 
Paris. Some additional facts regarding the crystallization of 
this remarkable mineral with some new figures may not be 
without interest to those who are especially interested in Ameri- 
can minerals. In addition to the crystals from the above men- 
tioned locality, I have also, through the kindness of Mr. Whit- 
man Cross, been provided with crystals from an entirely 
different locality, and with different associations and crystalline 
habits, which are especially worthy of description. 
The lenticular crystals which have already been described 
are from Topaz Butte, near Florissant, and about sixteen miles 
from Pike’s Peak. In studying them, the first point noticed is 
their great similarity in habit to those described and figured by 
N. v. Kokscharow,| from the Ilmengebirge, Urals, where they 
occur with the same associations on amazon stone. All of the 
forms mentioned by Kokscharow occur on the crystals from 
Topaz Butte, and besides them I have found no others. His 
figures also represent very closely the habit of the crystals. 
The specimens which I have examined include those in the 
collection of Prof. Gec. J. Brush, the Yale College cabinet, and 
two loose crystals from the collection of Mr. C. S. Bement, of 
Philadelphia. The forms which have been identified are as fol- 
lows: they are of especial interest because belonging to the 
rhombohedral-tetartohedral division of the hexagonal system.4] 
uo mpoledrons Ist Rhomb. 2d order. Rhomb. 3d order. Prisms. 
oraer. 
r, 1011, +1 p, 1123, 7 3-2, x, 1322, —r 3-3 a, 1120, 7-2 
2, 0111, —1 Pj, 2113, 0 3-2, %,, 1232, — 1 3-3 fin WOMO, —J/ 
d, 0112, —4 0, 4223, 1 4-2, Gy MBS SpyP 3-3 
io, (=) 
*This Journal, III, xxiv, 282. + Bulletin No. 20 of U. S. Geological Survey. 
{ This Journal, II], xxix, 249. § This Journal, III, xxxii, 210. 
|| Materialien zur Mineralogie Russlands, ii, 322. 
§; As these forms are tetartrohedral, + should be understood before each of the 
Dana symbols. 
