Multiphase inclusions are key indicators when identifying emeralds and determining their origin. Gemologists look for the jagged three-phase inclusions in stones of Colombian origin or blocky two-phase inclusions in Brazilian or Zambian emerald. These multiphase inclusions typically require higher magnification and considerable maneuvering of the emerald to get a precise view.
Recently, the Carlsbad laboratory received a 9.02 g rough emerald from Lucas Fassari (Costa Mesa, California). The rough had an eye-visible mobile inclusion (see above) consisting of a CO2 gas bubble and salt crystals suspended in a fluid. The emerald was identified using a handheld spectroscope and optical properties. It was determined to be of Colombian origin by its jagged three-phase inclusions and crystals that had characteristics of pyrite and calcite. The mobile inclusion was quite large in relation to the rough emerald, which measured 28.76 × 14.82 × 12.83 mm, including its calcite and shale matrix. The CO2 bubble measured approximately 4 × 3 mm.
Mobile inclusions of this size are captivating to observe, and to see one in an emerald adds more allure to the piece. Cutting this specimen into a faceted gemstone would lose what makes this rough emerald unique.
The Carlsbad and New York laboratories and schools will be closed on Monday, May 28 in observance of the Memorial Day holiday. These locations will resume regular business hours on Tuesday, May 29.