Joaquinite was first described by
George D. Louderback in 1909 from the Benitoite Gem Mine in
San Benito County, California. Early studies by Palache and Foshag (1932) proposed
orthorhombic symmetry and a preliminary formula, but detailed characterization remained incomplete for decades. Renewed interest followed discoveries in
Quebec and
Greenland, where
rare-earth elements were confirmed as essential components. Laird and Albee (1972) demonstrated that joaquinite is
monoclinic with
polysynthetic twinning, and later structural refinements by Cannillo et al. (1972) and Dowty (1975) clarified its
crystallography. Compositional variations led to the definition of the joaquinite group, including new strontium- and barium-dominant species approved by the
International Mineralogical Association. == List of joaquinite-group minerals ==