This Burmese ruby contains a storm of iridescent, needle-like rutile inclusions. Rutile inclusions, also called "silk," are common in ruby. When clustered closely together, some of them look like triangles or other geometric shapes. These “silk” inclusions can create the asterism seen in star ruby.
Innovative new treatments have also played a major role in satisfying the continued demand for ruby. In the early 1990s, gemological laboratories saw the introduction of chromium-diffused rubies (McClure et al., 1993). In the early 2000s, lead-glass filling of low-quality rubies reached international markets and became one of the most widespread—and most problematic—treatments in the gem trade (McClure et al., 2006). Also encountered in the early 2000s was beryllium diffusion of ruby, which made it possible to produce pleasing red colors from stones with strong brown or dark tones that would not respond to traditional heat treatment (Emmett et al., 2003). Rubies from Songea, Tanzania, for example, were dramatically improved with beryllium diffusion.
Demand has also been met by several new ruby deposits in the last decade. Mozambique has become the leading producer of gem-quality rubies since the discovery in Montepuez in 2009. More than two million carats of rough from Mozambique were offered at the first Gemfields rough ruby auction in 2014.