Sapphirine is a rare mineral, a silicate of magnesium and aluminium. Named for its sapphire-like colour, sapphirine is primarily of interest to researchers and collectors: well-formed crystals are treasured and occasionally cut into gemstones. Sapphirine has also been synthesized for experimental purposes via a hydrothermal process.

Typical colours range from light to dark sapphire blue, bluish to brownish green, green, and bluish or greenish gray to black; less common colours include yellow, pale red, and pink to purplish pink. Sapphirine is relatively hard (7.5 on Mohs scale), usually transparent to translucent, with a vitreous lustre.


Cause of Color :

Not characteristic.

Chemical Composition :

Complex Magnesium Aluminium Silicate – MgAl2SiO6

Crystal System / Forms :

Monoclinic System / Indistinct tabular crystals, fibrous to columnar aggregates.

Cuts & Uses :

Facetted cuts.

Hardness : 7 - 7.5
Lustre : Vitreous
Magnification :

Phase and crystal inclusions, fingerprints.

Optic Character :

Anisotropic, D.R.; Biaxial negative / positive

Pleochroism : Strong. Light Blue, Blue, Dark Blue (Shades of body color)
Refractive Index / Birefringence :

1.704 – 1.710 / 0.006

Simulants (with separation tests) :

Sapphire (optic figure, R.I., S.G., inclusions), Natural Spinel (optic character), Kyanite (birefringence, S.G., inclusions)

Sources :

Sri Lanka, Greenland, Madagascar.

Spectrum :

Color varies with iron percentage.

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