- The type of
twinning can be a
diagnostic tool in
mineral identification.
There are
three main
types of
twinning. The
first is
growth twinning which can...
-
Plagioclase almost universally shows a
characteristic polysynthetic twinning that
produces twinning striations on [010].
These striations allow plagioclase...
-
Sixlings are
common in aragonite.
Polysynthetic twins are
similar to
cyclic twins through the
presence of
repetitive twinning; however,
instead of occurring...
- it as soon as a dome is cut. The
Journal of
gemmology mentions polysynthetic twinning (parallel lines). The star
effect occurs in
other sapphire colours...
- in
extinctions viewed under cross polarization.
Ulexite displays polysynthetic twinning parallel to the elongation,
along {010} and {100} (Murdoch, 1940)...
-
acicular to
tabular prismatic Twinning Common as
contact or
penetration twins on {100} and {201}.
Polysynthetic twinning also present.
Cleavage Perfect...
- tabular, prismatic,
rhombohedral crystals, m****ive or
granular Twinning Polysynthetic twinning common Cleavage None –
parting in 3
directions Fracture Conchoidal...
- that it
actually abides by two
twin laws.
Polysynthetic twinning can
occur along its (001) and
another type of
twinning can
occur parallel to its optical...
-
prismatic crystals; tabular, rhombic,
flattened along [010]
Twinning Polysynthetic twinning produces a grid
pattern on [100]
Cleavage Perfect on [001]...
- jadeite. It
crystallizes in the
monoclinic system with prismatic,
typically twinned forms,
though usually anhedral. Its
space group can be P2/n or C2/c depending...
