In Europe,
moonstone is considered the birthstone for June, although in the
United States it shares that distinction with Alexandrite and
Pearl. Moonstone is 6 - 6.5 on the Mohs scale of hardness. Fine
Moonstone is quite rare and becoming rarer. It is mined in Sri
Lanka and Southen India. The rainbow variety can also be found
in Madagascar. Moonstones are usually cut in a smooth-domed
cabochon shape to maximize the effect. Sometimes they are carved
to show a man-in-the-moon face. Moonstone beads also display the
sheen very well and are simply stunning against a black dress.
Click here for a picture in natural form.
Click here for more faceted and natural specimens.
Description:
Moonstones come in a variety of colors. The body color can range
from colorless to gray, brown, yellow, green, or pink. The
clarity ranges from transparent to translucent. The best
moonstone has a blue sheen, perfect clarity, and a colorless
body color. Moonstone almost seems magical with a ghostly
shimmering glow floating in a crystalline material. The Romans
thought that moonstone was formed out of moonlight. Sometimes
moonstone will have an eye as well as a sheen. Another related
feldspar variety is known as Rainbow Moonstone. In this variety
of labradorite feldspar, the sheen is a variety of rainbow hues.
Chemistry:
The formula for Moonstone, Oligoclase, a variety of Feldspar is
Na(90-70%)Ca(10-30%)(Al, Si)AlSi2O8,
Sodium calcium aluminum silicate. Oligoclase is not a well known
mineral but has been used as semi-precious stone under the names
of Sunstone and Moonstone. Sunstone has flashes of reddish color
caused by inclusions of hematite. Moonstone shows a glowing
shimmer similar to labradorescence, but lacking in color. The
display is produced from lamellar intergrowths inside the
crystal. These intergrowths result from compatible chemistries
at high temperatures becoming incompatible at lower temperatures
and thus a seperating and layering of these two phases. The
resulting shimmer effect is is called "schiller" or "adularescence",
caused by a ray of light entering a layer and being refracted
back and forth by deeper layers before it exits the crystal.
This refracted ray has a different character than when it went
in and produces the moonlike glow. Oligoclase is a member of the
Plagioclase Feldspar Group. The plagioclase series comprises
minerals that range in chemical composition from pure NaAlSi3O8,
Albite to pure CaAl2Si2O8,
Anorthite. Oligoclase by definition must contain 90-70% sodium
to 10-30% calcium in the sodium/calcium position of the crystal
structure. The various plagioclase feldspars are identified from
each other by gradations in index of refraction and density in
the absence of chemical analysis and/or optical measurements.
All plagioclase feldspars show a type of twinning that is named
after Albite. Albite Law twinning produces stacks of twin layers
that are typically only fractions of millimeters to several
millimeters thick. These twinned layers can be seen as striation
like grooves on the surface of the crystal and unlike true
striations these also appear on the cleavage surfaces. The
Carlsbad Law twin produces what appears to be two intergrown
crystals growing in opposite directions. Two different twin
laws, the Manebach and Baveno laws, produce crystals with one
prominant mirror plane and penetrant angles or notches into the
crystal. Although twinned crystals are common, single crystals
showing a perfect twin are rare and are often collected by twin
fanciers.
Legends, Myths and Healing
Properties:
 Moonstone
is believed to possess energy that is balancing, introspective,
reflective, and lunar. It is capable of helping one with the
changing structures of ones life on the physical, emotional,
mental, and spiritual levels. It is a stone for hoping and
wishing. It can be used to alleviate emotional tension and to
enhance the positive attributes of creativity and
self-expression. It cleanses negativity. |
|
){kind=link}