-
cleavage is mica,
which cleaves in a
single direction along the
basal pinacoid,
making the
layers seem like
pages in a book. In fact,
mineralogists often...
-
intersect at
about 120
degrees in a three-fold
direction of the
basal pinacoid.
Black star
sapphire is
found in Thailand, Cambodia, Tanzania, Australia...
-
tabular to
prismatic crystals with an
obvious pinacoid termination. It has four
prism faces and two
pinacoid faces to form a
pseudohexagonal crystal. Although...
- are
generally tabular in
habit owing to the
predominance of the
basal pinacoid;
numerous smooth bright faces are
often developed on the
edges and corners...
-
Predominant crystal faces (prism - prismatic,
pyramid -
pyramidal and
pinacoid - platy).
Crystal forms (cubic, octahedral, dodecahedral). Aggregation...
- plates, or
short prisms,
showing hexagonal dipyramids,
pyramids and
basal pinacoid. {1010}, {1011} and {0001} dominant. May also be
tabular or rhombohedral...
-
parallel to
their length between crossed nicol prisms.
Twinning on the ortho-
pinacoid is
usually evident. The
structure of the
aluminosilicate framework is the...
- intergrown.
Crystals are
squat and when
single tend to lie on the
basal pinacoid. The
pinacoid {001} and the
dipyramid {113} are the
dominant forms; all the faces...
- A
combination of pink
pinacoid and
green basal terminations on a dark core of elbaite...
- faces, also as
tapering six-sided
pyramids that can be
truncated by the
pinacoids. Also m****ive,
lamellar and in
small grains in
sulfide ore
bodies Cleavage...
