A doubly-terminated tourmaline with colour-zoning. Although the green zone at the end of the flat termination grades a bit, the light green banded and yellow zone at the other end begins with an abrupt change from the dark zone. Stak Nala has been known for producing tourmaline crystals with abrupt zoning changes, although the yellow in this crystal is uncommon. This crystal is in excellent condition. From the Pete Richards collection, an excellent colour-zoned elbaite.