Description:
Diopside is an important rock forming mineral in several
metamorphic and basic to ultra basic igneous rocks,
also found in meteorites. Diopside is a part of an important
solid solution series of the pyroxene group. The series
includes the minerals hedenbergite, CaFeSi2 O6, and
augite, (Ca, Na)(Fe, Mg, Al)(Al, Si)2 O6. A series occurs
when ions (in this case iron and magnesium) can freely
substitute between each other. Diopside is the magnesium
rich end member of the series. The diopside-hedenbergite
series is analogous to the amphiobole, tremolite- actinolite
series.
Diopside has several varieties, including a chromium-rich
gem variety called chrome diopside. Violan is rare blue
variety found in some localities in Italy. There is
also a green "cat's eye" variety that contains
minute inclusions, probably of rutile, that reflect
light in such a way as to produce a lively linear luminscence
within the crystal. Still another variety is quite dark,
with included rutile needles aligned so as to produce
a 4-rayed star, hence the name star diopside. Ordinary
diopside is typically white or green and can have a
nice glassy luster. While the color of chrome diopside
is much brighter, many specimens of ordinary diopside
are also cut for gemstones. Mineral specimens of diopside
can be very striking in appearance, and of interest
to mineral collectors. |