Tourmaline (With Core Altering To Lepidolite)
Pederneira Mine, Minas Gerais, Brazil
Cabinet, 10.0 x 1.8 x 1.4 cm
Ex. Dr. Stephen Smale
This gemmy, lustrous, deep green elbaite is from the richly productive Pederneira pegmatite. The main single crystal is flanked by smaller gemmy, green, elbaite crystals. The central 2/3 of the major crystal in particular are very gemmy, though the top is darker and not so translucent. The termination is superb, and extremely sharp and lustrous, making amends for the dark color there. All in all, a fine tourmaline. However, there is an added bit of interest at the base where the bottom portion internal to the crystal has started to alter into lepidolite! This crystal is caught in the process of becoming a lepidolite pseudomorph after tourmaline, in the early stages, and you can see here how it must occur from the ground up, with the outer casing of tourmaline shedding along the way after the inside changes over time somehow.