Secondary inclusions

Secondary fluid inclusions are trapped in the healed fractures of a crystal that have been broken after its formation. In time, it can happen millions of years after the crystals have been formed. It can be broken due to tectonic movements in the area, and later its fractures were healed by circulating fluids, different to the primary fluids responsible for the host crystal formation. In some way, they are similar to epigenetic solid inclusions also formed in fractures, happening after the host crystal had finished its growth.

Studies of fluids contained in secondary inclusions are not informative to determine the original crystal growth conditions, but they can reveal the evolution of pressure, temperature and chemistry of fluids in the same deposit during its posterior geological history.

Plotting for typical location of a veil of secondary inclusions in emerald crystal, crossing through different growth zones marked by color zoning and reaching the surface of the crystal. Brazilian emerald, immersion, field of view 5 mm.