This is a beryl crystal, variety aquamarine, from Mocuba, Mocuba District, Alto Ligonha District, Zambezia Province, Mozambique. I do not know much about this locale other than it produces gem quality aquamarine for the gem- jewelry trade and mineral specimens are uncommon. Beryl is clear and colorless in it’s pure form however it can be found in a variety of colors from red to emerald depending on trace elements in the crystal lattice. Beryl is a beryllium-rich silicate that contains the elements Be, Al, Si, and O. This crystal is transparent with internal flawing. The top has multiple terminations and the base has a flat concoidally fractured surface. It contains hematite crystal and minor oxide inclusions just under the surface and the prism faces host varying degrees of mica and feldspar crystals This is a large thumbnail that measures 1 1/8 x 1/2 x 1/2 inches or 28 x 12 x 12 mm.