Dyed Fluorite
Two pieces of green rough weighing 358.03 and 454.27 ct (figure 1) were recently sent to the Carlsbad laboratory for an emerald identification and origin report. Standard gemological testing could not be performed due to the rough surfaces and size of the stones. Raman spectroscopy was used to aid in the identification (figure 2), and the Raman spectra were consistent with the mineral fluorite.
and a known emerald sample.
Internally and externally, both pieces showed typical massive habit fluorite features. Small octahedral crystals were scattered along the surfaces, and perfect cleavage in four directions was documented. Cleavage is not a gemological property of emerald, and octahedral cleavage is a key identifying feature for fluorite. Weak color banding could be seen with diffused lighting, but the most abnormal observation with both of these stones was the presence of obvious dye concentrations along their fractures (figure 3).
Fluorite naturally comes in a wide range of colors and can have multiple colors in a single crystal. These stones are a careful reminder to analyze every stone thoroughly for proper identification and to detect the most uncommon of treatments.
