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Fluid inclusions in Peridot examined under varying lighting environments.
Apart from the numerous inclusions that are typically associated with peridots, they may also contain fluid inclusions that can vary in appearance. Often, the partially healed fractures contain randomly shaped and placed fluid inclusions. On occasion however, they appear in the form of fluid lining within these partially repaired fractures.
Such is the case at hand. The importance of applying varying lighting techniques is demonstrated in the following 3 pictures. The photographed area contains the said fluid lining along with a delicate fingerprint edge that are part of a partially healed fracture. The said area is examined under bright-field, a combination of bright-field and fiber-optic and then with oblique fiber-optic illumination only.
Under bright field, the entire area does not appear very prominent. Under a combination of both methods, the area comes to life and more inclusions in the surrounding vicinity start to show up. But under oblique fiber-optic illumination, the entire game changes. Due to the reflective nature of these fluid inclusions, the entire area lights up and every little inclusion within the area becomes crystal clear.
Oblique illumination is a technique whereby light is projected from a sideways slanting angle to reveal features with higher contrast as compared to when viewed with bright-field. This is achieved by positioning one or both goosenecks on either side of the sample at varying angles. And as the pictures illustrate, a must have weapon that should be present in every gemologist’s arsenal.
Sheikh Fahad Abbas – GIA GG, AJP
Founder & Owner – Gemystique®
