"Blue Cap" Tourmaline - Himalaya Mine, Mesa Grande, San Diego Co., California, USA
Ex Robert Scheck via Bill Larson, 1984
 
An extremely rare elbait tourmaline "Blue Cap" from the Himalayan mine and NOT from the find of 1972 in the Queen Mine, San Diego Co Blue-capped tourmalines from the Himalayan mine are much rarer. This 4.2 cm elbaite shows the blue endface phenomenon best in daylight or in a display case when the light falls from above. In daylight, the blue appears brighter than under artificial light.
Of particular note is how far the blue zone has grown into the interior of the crystal. The tourmaline has a pink core overgrown by a minimal powder blue transparent zone. Due to this outer zoning, the crystal appears in a wide variety of tones between violet and pink, depending on the incidence of light. 
A historically rare collector's item of this rare tourmaline Art.