garnetiferous
layer, with more or less wavy upper surface, which could be traced
continuously for over 50 feet. The garnetiferous band itself is nowhere
over 1-1/2 inches wide and is a rather finely granÂular crystallization
of quartz, feldspar, and garnet, the crystals of garnet constituting
about half of the band, but few of them exceedÂing one-fourth inch in
diameter. In places the main garnet layer is paralleled below at a
distance of 1 to 2 inches by another similar band less rich in garnets.
Outside these bands garnet occurs in the pegmatite in graphic
intergrowth with quartz and in small irregular masses between the other
minerals. The pegmatite shows very different characters below and above
these garnetiferous layers. The rock just above is much coarser, does
not show graphic texture, and does show albite, in part massive and in
part of the clevelandite variety, as its dominant feldspar, though it
contains also some ortho-clase in graphic intergrowth with quartz.
Muscovite in brush-shaped and rosette-shaped intergrowtlis with quartz
is also more abundant above than below the garnet layer, and black
tourmaline is common in places in graphic intergrowth with quartz. The
pegmatite just below the garnetiferous band is a rather fine-grained
graphic intergrowth of quartz and orthoclase showing a more or less
radial structure trending about at right angles to the garnetiferous
layer.
Only
small portions of the feldspar are of commercial grade for pottery
purposes, both muscovite and biotite being quite abundant.
Quartz
is mainly present in intergrowth with other minerals or as crystals
developed on the walls of the pockets. Most of it is white or light
gray, but some small amounts of rose quartz are found.
The
muscovite commonly occurs with quartz in brush-shaped or rosette-shaped
intergrowtlis averaging 4 to 5 inches in diameter and disposed with
utter irregularity throughout the pegmatite mass. Some of these grade
at their outer borders into spearhead-shaped bundles of muscovite
penetrating the neighboring quartz masses, the latter being apparently
continuous with the quartz of the fine muscovite intergrowtlis. No
plate mica occurs, and the only possible utilization of the mineral is
as scrap mica.
Biotite
is abundant, though much less so than the muscovite. It occurs in small
lath-shaped crystals, oriented in every direction in the pegmatite
mass. A few are a foot long and 2 inches wide, but the majority do not
average more than 2 inches long and 1 inch in width. A central " stalk"
of biotite with smaller lath-shaped crystals radiating from it is not
uncommon.
Lepidolite
is abundant near the pockets in irregular aggregates of small plates or
prisms one-sixteenth to one-eighth of an inch across, and in larger
more or less curved crystals. In many places it forms narrow borders
about hexagonal muscovite plates, the two varieties of mica being
crystallographically continuous. Mr. Wade reports one
