Minerals of the Clear Clear Recreation Area

Joaquinite

Found at:

Gem Mine
Junnila Mine Victor Mine
Mina Numero Uno

Named for Joaquin Ridge. Joaquinite, which was discovered in 1909, is a pretty rare mineral. It is most renown for its association with other exotic minerals such as the sapphire blue benitoite, the red-black neptunite and the snow white natrolite. If it were not for these minerals which are found in San Benito County, California; joaquinite might not be so well known. It forms typically small, sparkling, brown to yellow, well formed crystals usually scattered on massive green serpentine.

Joaquinite is a product of some very unusual hydrothermal solutions. These solutions contained the elements titanium, niobium, lithium, barium, niobium, manganese, fluorine, cerium and several others. Anyone of them by themselves is not that unusual, but together in one solution and in such high concentrations is quite unusual. How they came to be combined like this is not yet well understood, but their product of unusual silicate minerals is much appreciated.

Joaquinite lends its name to a group of similar minerals. The Joaquinite Group members are unusual cyclosilicate minerals. They are some of only a few four membered ring silicates. These silicates have four silicate tetrahedrons linked into a ring forming a distorted square-like structural element. The general formula of this group is A6(Ti, Nb)2Si 8(O, OH) - H2O; where A can be either sodium, barium, cerium, iron, manganese and/or strontium. Joaquinite and strontiojoaquinite are monoclinic, while the other members are orthorhombic.

These are the members of the Joaquinite Group:

  • Bario-Orthojoaquinite
  • Orthojoaquinite
  • Strontiojoaquinite has a wide range of habits and colors; from equant, rounded crystals with light to sun-yellow colors, to spade-shaped crystals, with the same color ranges. This species does not fluoresce and can be found in the same rock type as the benitoite.
  • Strontio-orthojoaquinite

Copyright ©, 2005 Three Rocks Research. Updated January 26, 2005