Motukoreaite
| Motukoreaite | |
|---|---|
Yellow-white balls of motukoreaite held together by phillipsite | |
| General | |
| Category | Sulfate and Carbonate mineral |
| Formula | Mg6Al3(OH)18[Na(H2O)6](SO4)2·6H2O (possibly more than one species) |
| IMA symbol | Mtu |
| Strunz classification | 7.DD.35 |
| Dana classification | 17.1.7.1 |
| Crystal system | Trigonal |
| Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2/m) |
| Space group | R3m |
| Unit cell | a = 9.172(2) Å, c = 33.51(1) Å, Z = 3 |
| Identification | |
| Color | Colorless, white, pale yellow, pale yellow-green |
| Cleavage | Good on {0001}, perhaps a parting |
| Tenacity | Sectile, flexible |
| Mohs scale hardness | 1–1.5 |
| Luster | Dull |
| Streak | White |
| Diaphaneity | Semitransparent |
| Specific gravity | 1.43–1.53 |
| Optical properties | Uniaxial (+) |
| Refractive index | nα = 1.510, nβ = 1.510 |
| Birefringence | δ = 0.012 |
| References | |
Motukoreaite is a mineral with formula Mg6Al3(OH)18[Na(H2O)6](SO4)2·6H2O (possibly more than one species). The mineral is named for Motukorea, the island in New Zealand where it was discovered. Motukoreaite was first noted in 1941 and officially described in 1977.