Unveiling the Mysteries of a 10.02ct Burmese Ruby: A Gemological Study on Low Heat Treatment

Recently, I had the opportunity to examine a remarkable 10.02ct Burmese ruby entrusted to me by a customer for a Laboratory opinion. What initially seemed like a straightforward assessment quickly turned into a fascinating investigation due to conflicting certification reports regarding its Heat treatment status.

According to records, this ruby was first certified in December 2007 by Government Laboratory as a "No Heat" Burmese ruby. However, a subsequent certification in December 2018 by another very known Private Laboratory categorized the same stone as a "Heat treated (Ha)" Burmese ruby. Both reports astonishingly aligned in terms of measurements and other parameters, except for this crucial distinction in Heat treatment.

To resolve this discrepancy, I embarked on a meticulous examination, starting with standard tests such as Refractive Index (RI), Specific Gravity (SG), and Spectrum analysis to confirm the stone’s identity. However, my primary focus lay in microscopic observation, as internal characteristics, particularly inclusions, provide definitive clues about this ruby's treatment history.

Under the microscope, I was initially surprised to find intact crystals within this ruby, because Heat-treated Rubies or Sapphires exhibit burst crystals resembling snowballs. This is a good indication of a stone that has not undergone any heat treatment.

However, upon closer inspection, I identified a distinct white patch and observed broken silk (needles), alongside an infected fingerprint inclusion. These observations pointed towards a form of heat treatment known as LTHT (Low Temperature Heat Treatment), as documented in an article from G&G by GIA Gemological Institute of America.

The article highlighted LTHT as a treatment method that preserves crystal integrity while rarely altering silk inclusions, creating a unique pattern that aligns with my findings. This discovery underscored the importance of staying abreast of industry research and knowledge to accurately assess gemstones in a rapidly evolving landscape.

But my further consideration was given to the possibility of incidental heating during jewelry polishing, which could account for the minor features observed on this ruby's surface. Despite this, the presence of characteristic inclusions indicated a treatment history, albeit unintentional and indirect.

In conclusion, my comprehensive analysis led me to conclude that while the Burmese ruby in question has undergone LTHT, it remains a valuable gemstone suitable for exquisite jewelry pieces. I am confident that this detailed examination not only clarifies the ruby's treatment status but also enhances our understanding of gemological practices for the benefit of our clientele and the broader gemstone community.

For those interested in delving deeper into gemological insights, I recommend reading the referenced article from G&G, which provides additional context on LTHT treatments.

Thanks & Regards,

Bhrugu A. Pattani