Serendibite

Serendibite is an extremely rare silicate mineral that was first discovered in 1902 in Sri Lanka by Dunil Palitha Gunasekera and named after Serendib, the old Arabic name for Sri Lanka.

Serendibite
A relatively sharp, vitreous black crystal of serendibite from Le Oo, in Mogok Township, measures: 16 x 13 x 8 mm
General
CategoryInosilicates
Formula
(repeating unit)
(Ca,Na)2(Mg,Fe2+)3(Al,Fe3+)3[O2|(Si,Al,B)6O18]
Strunz classification9.DH.40
Dana classification69.2.1a.6
Crystal systemTriclinic
Crystal classPinacoidal (1)
(same H-M symbol)
Space groupP1
Identification
Colorpale yellow, blue-green, greyish blue, black
TwinningPolysynthetic on {0-11} is common
CleavageNone Observed
Mohs scale hardness6.5 - 7
LusterVitreous
StreakWhite
DiaphaneityTransparent, Translucent,Opaque
Specific gravity3.42 - 3.52 (measured) 3.47 (calculated)
Optical propertiesBiaxial (+)
Refractive index1.701 - 1.706
PleochroismVisible,strong, color: green, blue, yellow, bluegreen, light yellow
2V angleMeasured: 80°
Dispersionstrong
References[1][2]

The mineral is found in skarns associated with boron metasomatism of carbonate rocks where intruded by granite. Minerals occurring with serendibite include diopside, spinel, phlogopite, scapolite, calcite, tremolite, apatite, grandidierite, sinhalite, hyalophane, uvite, pargasite, clinozoisite, forsterite, warwickite and graphite.[2]

Crystal from Mogok, Myanmar, size: 1 cm x 0.7 cm x 0.7 cm

See also

References

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