Sinhalite

This article is about the mineral. For the racehorse, see Sinhalite (horse).

Sinhalite
General
Category	Mineral
IMA symbol	Shl[1]
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

1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
2. "Sinhalite". Mindat.org.
3. "Sinhalite gemstone information". Gemdat.org. Retrieved 21 March 2019.