Sinhalite is a borate mineral with formula MgAl(BO4).[2]
| 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 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
edit- ^ 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.
- ^ "Sinhalite". Mindat.org.
- ^ "Sinhalite gemstone information". Gemdat.org. Retrieved 21 March 2019.
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