Joaquinite-(Ce)
| Joaquinite-(Ce) | |
|---|---|
| General | |
| Category | Silicate |
| Formula | NaBa2Ce2Fe2+Ti2Si8O26(OH)·2H2O |
| Strunz classification | 9.CJ.05 |
| Space group | P21/m |
| Unit cell | a = , b = , c = , β = °; Z=2 |
| Identification | |
| Color | Dark grey |
| Crystal habit | Tabular crystals |
| Twinning | Polysynthetic on {001} |
| Cleavage | Good on {001} |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 5.5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Translucent |
| Optical properties | Biaxial (-) |
| Pleochroism | Strong red-brown |
| Ultraviolet fluorescence | None |
| Other characteristics | Internal reflections strong red-brown |
Joaquinite-(Ce) is a rare silicate mineral with the chemical formula NaBa2Ce2Fe2+Ti2Si8O26(OH)·2H2O. It crystallizes in the monoclinic system with orthorhombic pseudomorphism and exhibits tabular crystals.
Crystallography
Joaquinite-(Ce) belongs to the monoclinic crystal system with orthorhombic pseudomorphism. It forms in point group 2. Twinning is polysynthetic on {001}, and the mineral shows good cleavage on {001} with uneven fracture.[1] The average hardness is 5.5 on the Mohs scale.[2]
Optical properties
The mineral is translucent, with a vitreous lustre and white streak. It is biaxial and displays strong red-brown pleochroism. Internally, it shows strong red-brown reflections under crossed polars.[1]
Environment
Joaquinite typically occurs in natrolite veins cutting a glaucophane schist, as inclusions in a serpentinite body, and in fennitized gneisses and alkalic syenites.[1]
Associated minerals
It is commonly found in association with aegirine, barylite, benitoite, eudialyte, natrolite, neptunite, and orthojoaquinite-(Ce).[1]
Minerals with optical similarities include verplanckite, baotite, cerchiaraite, titantaramellite, taramellite, nagashimalite, strontiojoaquinite, strontio-orthojoaquinite, bario-orthojoaquinite, and orthojoaquinite-(La–Ce).[1]
Type locality
The type locality for joaquinite is the Dallas Gem Mine in the Benitoite Mine in California, USA.[1]