TR28AF6: Doubly terminated floater crystal with well-defined faces and edges and complete terminations, one of them simple and pinacoidal, the other showing an unusual polycrystalline growth with a deep structural incision that seems to break the crystal longitudinally into two symmetrical parts. The sample is transparent, bright, and vividly colored.

The Chivor mining district corresponds to the historical group of emerald workings located in Chivor Municipality. It was already known and exploited in pre-Columbian times by the indigenous Muisca peoples.

Geologically, the Chivor mining district forms part of the Eastern emerald belt of Boyacá. Emerald mineralization is hosted in Cretaceous sedimentary sequences, mainly black shales and bituminous limestones of the Guavio and Macanal formations. The emeralds occur in hydrothermal veins related to Andean tectonic fracturing, resulting from the interaction between beryllium-rich fluids and chromium- and vanadium-bearing host rocks. Typical mineral associations include Calcite, Dolomite, Pyrite, and occasionally Parisite and Fluorite.
Chivor mining district, Municipio Chivor, Eastern Emerald Belt, Boyacá Department  Colombia

Specimen size: 3.3 × 0.8 × 0.7 cm = 1.30” × 0.31” × 0.28”