Micro-World Gems & Gemology, Winter 2020, Vol. 56, No. 4

Uncommon Inclusion of Lazurite in Ruby from Mogok, Myanmar

Bright blue lazurite inclusion in Mogok ruby.
Lazurite inclusion in Mogok ruby from Myanmar (transmitted light and oblique illumination). Photomicrograph by Kyaw Thu; field of view 0.25 mm.

A parcel of small rubies was received for identification at the S Gemmological Institute (SGI) gem lab in Yangon, Myanmar. Based on chemical, spectroscopic, and standard gemological testing, they were determined to originate from the Mogok Stone Tract in Myanmar. One faceted ruby contained a small blue crystal inclusion with what appeared to be a pyritohedron shape but an uncommonly seen bright blue color (see above). This inclusion was identified by Raman spectroscopy as lazurite.

A blue lazurite inclusion was previously reported to have been found in a 5.09 ct Burmese ruby and a 1.40 ct ruby from Namya, Myanmar (Spring 2012 Lab Notes, pp. 51–52). Also, blue lazurite mineral has previously been detected in 1.02 ct light gray Burmese spinel (Spring 2019 Micro-World, pp. 112–113).

According to the literature and our knowledge of inclusions in rubies from Mogok, this blue mineral is rare as an inclusion in Burmese rubies.

Thuzar Aung is a senior gemologist at the S. Gemmological Institute (SGI) in Yangon, Myanmar.