axis
is yellowish brown or ocreous yellow to reddish brown, the one
perpendicular to this light yellow, absorption c'>a' in which C'
lies nearest the prism axis. The refractive index is high—at least
greater than that of monobromnaphthalene, 1.654.
The
name carlosite is suggested for this mineral, from the nearby San
Carlos peak, one of the highest points of that part of the range.
Benitoite
and carlosite occur as individual disseminated crystals in narrow
veins in a basic igneous rock or in a schist which has been
considerably altered by the solutions that formed the veins. The
benitoite is apparently restricted to the veins, the carlosite also
occurring in the neighboring parts of the wall rock. The chief gangue
of the veins is a soda rich zeolite. The properties of carlosite and
the nature of the gangue were determined on small and unsatisfactory
quantities, as the collectors were interested in the supposed sapphires
and not in its matrix. The writer has recently been able to collect
specimens of the matrix and crystals of carlosite and expects shortly
to make a more extensive report on the properties of benitoite and
carlosite, their paragenesis, etc.
