QUESTION OF THE WEEK
WHAT IS THIS?
CATEGORY: Unsolved Case Studies
LEVEL: Difficult
PURPOSE: Research
DESCRIPTION
The concerning emerald ought to be coming from Chivor mine in Colombia. It concerns a rough crystal with one unknown inclusion and one unusual three-phase inclusion. The picture shows 4 different images, all photographed perpendicular to the optical axis of this emerald.
OBSERVATIONS
Fig. (1 and 2) By observing the “unidentified” inclusion (0,1mm x 0,17mm) on microscope between crossed polarizer’s with ¼ lambda retardation plate, using transmitted diffused light without immersion, it shows the presence of an inclusion with attribution similar to a zircon inclusion in corundum. There is one more inclusion like this, with the same character, but is difficult to observe even with the use of immersion cell due to its depth in the crystal.
Fig. (3) The same unknown inclusion observed in the same direction, using only diffused transmitted light. This time no polarizer’s or retardation plates were used, but observed on microscope in immersion cell.
Fig. (4) This three-phase inclusion shows an unusual phenomenon. Red arrow points out to the solid phase/crystal, which shows again an inclusion. The cubic crystal (Halite?) itself measures (0,05mm x 0,05mm).
CONCLUSION
- The first inclusion (Fig 1,2 & 3) remains until now (29-7-2018) unidentified. The general question being: could this be a ZIRCON inclusion, as this would be rare? To my concern, it’s important that it can be visually identified.
- How would this three-phase inclusion (Fig 4) be defined and what is the inner inclusion in this crystal (a negative crystal, a fluid inclusion or another?).
The reason for this post is to share this image amongst other gemologist all around the world to share their knowledge in order to resolve this matter. As a gemologist I understand that it is hard to impossible to diagnose a gemstone/inclusion without researching it yourself, but the possibility remains that this inclusion is diagnostic to a colleague gemologist somewhere in the world.