Sinhalite

Sinhalite
General
Category	Mineral
Crystal system	Orthorhombic
Identification
Color	White, gray, grayish-blue, pale to dark brown, yellow, yellowish-brown, greenish-brown, green, brownish-pink, pale pink
Crystal habit	Grains, rolled pebbles, irregular masses. Rarely euhedral crystals.
Cleavage	None
Fracture	Conchoidal
Mohs scale hardness	​6 1⁄2-7
Streak	White
Diaphaneity	Transparent, translucent
Specific gravity	3.46 to 3.50
Density	3.475-3.5
Optical properties	Biaxial (-)
Refractive index	1.665 to 1.712
Birefringence	0.036 to 0.042
Pleochroism	Trichroism: green, light brown, dark brown
2V angle	56°
Dispersion	0.018
Ultraviolet fluorescence	None

Sinhalite is a borate mineral with formula MgAl(BO₄).^[2]

Sinhalite was first found in Sri Lanka (Ceylon) in 1952, and was named from Sinhala - the Sanskrit name for Sri Lanka.^[3]

Gemstone quality Sinhalite can also be found in Madagascar, Tanzania and Myanmar (Burma). The most commonly seen color of Sinhalite are white to gray, grayish-blue or a shade of brown ranging from pale to dark. Pale pink and brownish pink crystals can be found in Tanzania.

References

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