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What it is:
A metamorphic rock with a complex composition from Myanmar
(Burma). Maw-Sit-Sit is the name of the area in Burma where this mineral is found.
Maw Sit Sit is a rock, composed from at least six different minerals as main
constituents. They can vary greatly in their relatives amounts and therefore the
rock may vary strongly in its visual aspect as well as in its specific gravity
value. The name Maw Sit Sit was given to this arggregate metamorphic rock by the
locals who live near Kansi and Namshawa in North Burma (Myanmar).
The following is very complex and reading it is not for the faint of
heart:
The main constituents of Maw Sit Sit (Kosmochlor Jade) are:
- Chromite: small black relictic grains of metallic luster, mostly as
cores in black Kosmochlor aggregates, provided they show central grains of higher luster.
- Kosmochlor: forming nests of fine felty NaCrSi2O6 which are the
typical black spots in some Maw Sit Sit. Kosmochlor is the Cr-Analogon of Jadeite
NaAlCrSi2O6. The former name of Kosmochlor was Ureyite.
- Chrome-Jadeite: is encountered as larger single crystals forming
blocky mosaics. There is a solid solution or mixed series situation between Jadeite,
Chrome-Jadeite and Kosmochlor by the substitution of Aluminum by Chromium. In Maw
Sit Sit, usually various members of this series are present.
- Symplektite: a very fine mineral mixture, which cannot be
resolved microscopically. Symplekite is also green due to the chromium content of its
components.
- Chrome-Amphibole, or Amphibole: in larger crystals, depending on its
chromium contents green or grey. After their chemical composition they were
identified as Eckermanite bzw.
- Arfvedsonite Matrix: a mixture of bright mineral components
(Zeolite, Chlorite, Albite, and Serpentine) which fills the space between the minerals
named above. Fine veinlets mainly also consist of Zeolite, Chlorite, Albite or
Serpentine.
Formation Process:
Maw Sit Sit was formed in connection with a high-pressure low temperature rock
metamorphosis which affected an ultrabasic body locally. New formations of minerals
also took place after the culmination of the metamorphosis. Essentially it was a
metasomatic reaction between serpentinites and albite dykes. The chromium that is found in
most of the constituent minerals most probably stems from former chromite layers, which
have been dissolved during the metamorphic transitions. Remnants of chromite are sometimes
found as relicts within the Kosmochlor spots. The Maw Sit Sit deposit is placed at
the rim of a larger peridotite body that has been altered and serpentinized.
Sources:
The deposit is northern and close to the classical Jadeite location in Burma (
Tawmaw, Namshawa).
Other names currently applied to the material:
- Chloromelanite is an older mineral name of a pyroxene mineral that is
not part of Maw Sit Sit. It might also be in use due to its descriptive name
for" CHLOROS=GREEN" and "MELANOS=BLACK".
- Jade-Albite is a name composed of two mineral names which may occur
in Maw Sit Sit, but are subordinate and less frequent so that it is not justified to use
them for naming the stone.
Specifications:
Density: 2.5-3.2 g / cm3 depending on composition.
Refractive index = 1.766/1.781, SG=3.6
Colors: light green to black, monochrome, mottled or spotted, frequently with black
spots or white spots and veinlets.
Care & Maintenance:
It is not recommended that Maw Sit Sit be cleaned in an ultrasonic cleaner, or
exposed to temperature extremes. It is also recommended that care be taken in wearing Maw
Sit Sit because its hardness or durability is directly affected by the proportion and
composition of the above minerals.
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