The Pala Pegmatite of southern California is unusual for having pockets of lithium-rich minerals. The samples shown below are lithia pegmatites consisting of grayish-purple lepidolite mica (KLi2Al(Al,Si)3O10(F,OH)2 - potassium lithium fluoro-hydroxy-aluminosilicate) and deep pink rubellite tourmaline (Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 - sodium lithium hydroxy-boro-aluminosilicate).
The lithia pegmatites occur as pockets within the granitic Pala Pegmatite (Peninsula Ranges Batholith/Southern California Batholith). The Pala Pegmatite was emplaced about 104-105 million years ago, during the Albian Stage of the late Early Cretaceous.
Locality: Stewart Mine, NNE of the town of Pala, northwestern San Diego County, southern California, USA (33¼ 22Õ 52Ó North latitude, 117¼ 03Õ 49Ó West longitude)
Lithia pegmatite (3.9 cm across) with deep purplish-pink rubellite tourmalines in a matrix of dark lavender lepidolite mica.
Lithia pegmatite (4.9 cm across) with radiating spray of dark pinkish rubellite tourmaline in a matrix of pale lavender lepidolite mica.
Lithia pegmatite with radiating clusters of dark pinkish rubellite tourmaline in lepidolite mica matrix. (Colorado School of Mines Geology Museum, Golden, Colorado, USA)