Burma produces a majority of the worlds gem rubies by value, there are estimated to be at least 90 ruby mines in 17 countries. a popular source of late has been madagascar, where large deposits of ruby were discovered earlier this decade.

Most natural and heat-treated rubies tolerate the heat from bench operations. Generally, as long as rubies are allowed to cool before pickling and are not subjected to abrupt temperature changes.  Most rubies tolerate cleaners, solvents, and pickle, and they have no major issues with ultrasonic or steam cleaners.

Most glass-filled rubies on the market were probably too included or fragile to be faceted in the first place.  They are heavily fracture-filled with a highly unstable material that does not hold up to even the most comman jewelry practices.

Identifying glass-filled rubies: gas bubbles, wispy veil-like inclusions, repeated parallel parting, and blue color flash.  Glass filled rubies will also have inconsistent surfaces, which may include luster differences on the surface, dissolved surface spots or facet junctions, and a large amount of surface-reaching fractures.

Perhaps most disconcerting is that many glass-filled rubies are being offered for sale with no mention of treatment and very good prices. typically, the sizes of filled rubies on the market are between 5 and 10 carats.