| Sinhalite | |
|---|---|
 | |
| General | |
| Category | Minerals |
| Formula | MgAl(BO4) |
| 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.
