temperature.
Pallas mentions a specimen from Siberia, of a pale violet color, which
the heat of the hand caused to give out a white light merely ; the heat
of boiling water, a green light; and when on a live coal, it gave out a
bright emerald-green light that might be discerned from a distance. The
writer found that while handling a few specimens of this mineral in the
dark, phosphorescence resulted from the slightest attrition of the
specimens, either one with another, or with a nail or any hard
substance. In a dark room, at a temperature of about 8o° Fahr., the
Amelia County mineral shows a white, luminous glow, which is
intensified by the warmth of the hand ; when placed in boiling water,
it becomes green ; and on a heated iron plate, an intense
emerald-green. Most of the material is more or less flawed, so as to
render it very friable under touch. This variety is of a light-green
or a yellowish-green color,1 and seems to phosphoresce at
even a lower temperature than the more compact form. A stone cut from
this material and placed in a vial of warm water fluoresced distinctly
in a dark room, after being in the water a few minutes, thus giving a
new form of gem, that is, a fluorescent gem stone, though not hard
enough for continuous wear.
•Am. J. Sci. in., Vol. 28, p. 235, Sept., 1884.
