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 (33º 22’ 52” North, 117º 03’ 49” West).
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)