Untreated Ceylon Chrysoberyl 12.80 (CSC1280)

12.80 Carat
Diesel Color Shifter
Medium Dark 60
Very Lightly Included

GRADING REPORT CSC1280

• Identification: Natural Unheated & Untreated Color-Shift Chrysoberyl
• Carat: 12.80
• Shape: Oval/Cushion
• Measures: 16.10x13.45x7.65 (millimeter)
• Color Grade: Good
• Tone: M60
• Color Zoning: None
• Clarity: Very Lightly Included (silk or 'diesel')
• Cutting Grade: Very Good (precision re-cut by Conny F.)
  • Brilliancy: 80%
  • Depth: 56%
• Origin: Sri Lanka
• Treatment: None

Certificate No: CGJ6926

Overall Grade: Good

Comment: Formerly 14 carat chrysoberyl re-cut to 12.80 by Conny Forsberg in cold Sweden. A very unusual gem in at least two directions: Firstly, a typically Ceylon 'diesel' crystal and, secondly, a color shifter between yellow and green (see 'more images'). 'Diesel' is the name given to silvery crystals in sapphires from Sri Lanka which are heat treated to melt the crystal and then artificially colored. I've heard this does not work in chrysoberyl but never mind since we prefer our gems as made by earth and not colored by a machine. Interesting to note, that this silk is barely visible even under the lens but can be shown with the torch as in the close-up below, like a satellite view of earth. Diesel aside, the gem is 100% clean from all and any inclusions which is something in such a giant. As for the color-shift: You probably know that a strong color-change in a Chrysoberyl turns it into an Alexandrite, perhaps the most expensive matter on earth especially in such a size, but we here have only a color-shift between a honey yellow and a grass green, mostly mixed into one. Both features (diesel and CS) make the gem a tough customer in front of the camera but fun, as you can see from the number of images I made, and very interesting in person. For the collector of the unusual, and/or an utterly out-of-the way pendant or a daring gent's ring. 

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