. 
378 Review of Dana’s Mineralogy. 
of lateral, pearly or greasy to imperfectly vitreous. Color green or 
greenish, greenish-brown—dark olive-green. ‘Translucent to subtrans- 
lucent. Folia neither flexible nor elastic ; brittle. 
__* Composition, according to Jackson, (communicated to the author,) 
and Erdmann, (Jahresb. 1841, 174,) 
Chlorophyllite. Esmarkite, Brevig. 
Silica, 45°20 45:97 
Alumina, 27°60 32°08 
Magnesia, 9-60 10°32 
Protoxyd of iron,* 8:24 3°83 
Protoxyd of manganese, 4:08 0°41 
Water, . 3°60=98.32, J. 5:-49—98:10, E. 
- “ Traces of phosphoric acid were detected in the chlorophyllite. 
“ This mineral is closely allied to the hydrous iolite of Bonsdorff, but 
contains less water. Like that, it is found associated with iolite. Yields 
water before the blowpipe, and becomes bluish-gray, but fuses only on 
the edges. With carbonate of soda, effervescence takes place, and an 
opaque greenish enamel is formed, which becomes darker green in 
the reducing flame. 
* Obs. Chlorophyllite is usually associated with iolite in granite, and 
appears to proceed from the alteration of iolite. It often forms thin 
folia interlaminated with plates of iolite in the hexagonal prisms of this 
mineral. 
*“* The chlorophyllite of Jackson occurs abundantly in large prismatic 
and tabular crystals at Neal’s mine in Unity, Maine, associated with 
hornblende rocks containing iron and copper pyrites. The same mine- 
ral occurs with iolite at Haddam, Connecticut, and has been called 
Pinite. The Esmarkite of Erdmann is found in granite near Brevig in 
Norway. A 
‘The name Chlorophyllite, given this species by Dr. Jackson, is de- 
rived from ziegos, green, and gviloy, leaf, and alludes to its structure 
and color. The name Esmarkite was previously appropriated to @ 
variety of Datholite. 
It is probable that both the hydrous iolite of Bonsdorff and chloro- 
phyllite have proceeded from the alteration of iolite, and the hexagonal 
forms the crystals present may have been derived from the original 
iolite, instead of being the actual crystallization of the hydrous mineral. 
Gigantolite, Pinite, and Fahlunite, may also be altered forms of other 
minerals, and probably of iolite.” (pp. 306, 307 
i 6 an 
a If the iron in these analyses was protoxyd, why should the sum of the alu- 
mina and iron be equal ? (35-91 and 35.84, diff. 07.) We would suggest a query if 
it is not peroxide.—B. S., Jr. — 
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