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. The average hardness is 5.5 on the Mohs scale.
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.
Environment Joaquinite typically occurs in natrolite veins cutting a glaucophane schist, as inclusions in a serpentinite body, and in fennitized gneisses and alkalic syenites.
Associated minerals It is commonly found in association with aegirine, barylite, benitoite, eudialyte, natrolite, neptunite, and orthojoaquinite-(Ce).
Minerals with optical similarities include verplanckite, baotite, cerchiaraite, titantaramellite, taramellite, nagashimalite, strontiojoaquinite, strontio-orthojoaquinite, bario-orthojoaquinite, and orthojoaquinite-(La–Ce).
Type locality The type locality for joaquinite is the Dallas Gem Mine in the Benitoite Mine in California, USA.
References
See also
Joaquinite group
External links
Mindat.org – Joaquinite-(Ce)