Emerald

Emerald

The green variety of beryl, whose characteristic inclusions are as informative to a researcher as they are distinctive to the eye.

Overview

Emerald is beryl, a beryllium aluminium silicate, coloured green by chromium and vanadium. It forms where beryllium-bearing fluids meet chromium-bearing host rocks, a geologically unusual meeting that explains why fine emerald is so scarce.

Nearly all emeralds contain eye-visible inclusions. Colombian stones are known for three-phase inclusions of liquid, gas and a salt crystal, while Zambian and Brazilian stones more often contain mica platelets and amphibole needles from their schist host rocks.

Surface-reaching fissures are routinely filled with oils or resins to improve apparent clarity. Our emerald studies document the type and extent of such fillers and build reference collections of inclusion scenes by locality.