Class : Silicates
    Subclass : Cyclosilicates
    Crystal System : Monoclinic
    Chemistry : NaBa₂Ce₂FeTi₂(Si₄O₁₂)₂O₂(OH,F) · H₂O
    Rarity : Rare

Joaquinite is a rare cyclosilicate characterized by a pseudo-orthorhombic monoclinic crystal structure. Its chemical composition is complex, including titanium (TiO₂), barium (BaO) and rare earths (Ce, La, Nd, etc.), as well as iron and strontium. It is therefore considered today as a group and not as a species in its own right. It is often associated with its polymorph, orthojoaquinite-(Ce). Its name comes from its discovery location : Joachin Ridge near the famous Benitoite Gem Mine in California (USA). It is found in association with benitoite and neptunite in a natrolite vein cutting glaucophane schists in a serpentinite body (San Benito Co., California, USA) as well as in fenitized gneisses and alkaline syenites. Its crystals, often tabular or equant, reach up to 1.2 cm and show a marked cleavage according to {001}. Its hardness is 5.5 on the Mohs scale, and its measured density varies between 3.89 and 3.98. Ranging in color from honey yellow to brown, joaquinite is translucent to transparent with a vitreous luster.

Main photo : Joaquinite-(Ce) from Benitoite Gem Mine, California, USA © Stephan Wolfsried

Joaquinite is not known in the French underground.

Polysynthetic twins on {001} are common.

No fake known for this mineral.