Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara, Tanzania
An amazing, well crystallized specimen of tourmaline represents one of the rarest tourmalines ever found. This piece is very saturated green. Which upon very strong incandescent light turns to bright red, demonstrating the Usambara Effect. These are thought to be colored by both small amounts of chromium and vandadium, accounting for the rich color and color change effects. This piece is red under Chelsea (jadeite) filter and is chalky yellow in LW UV (most tourmaline is inert in UV light). It has a truncated prism so almost resembles a garnet in shape. The piece is crystallized in all directions except the bottom which has a small amount of matrix. It is undamaged, but there are multiple contacts on the back of the piece.
2.70 x 2.00 x 2.20 cm