While beryl from Erongo isn't unusual in the form of blue aquamarine, these bicolored beryls certainly are unusual for Namibia or ANY locale. This fine specimen came out of a famous pocket of the early 2000s, and is exceptional for the geometry, quality, and condition. Also, it has lustrous terminations, whereas many were dull. The majority of the flat-topped crystals are blue aquamarine, but the top couple of millimeters on each crystal dramatically alter to a moss green hue (which many people call heliodor, even though it is probably more accurately described as green beryl). The color contrast of the terminations of this pocket is unique in the mineral world, and they have been bought and sold at a premium for nearly 15 years now. No more of this style came out. This is among the best in size class, for quality, condition, aesthetics (and we handled many of them when we bought Charlie Key's collection circa 2010, to compare). This was most recently in the Namibian collection of Marshall Sussman.