Don’t be MisLEAD by Rubies

Grading and identifying gemstones can give you the opportunity to see inclusions you might have never known existed. Being someone who loves a little investigating, it is only the beginning when you see something you cannot understand and thats exactly what happened when I found out about Lead Filled Rubies.
While grading a packet of luscious red rubies, I was quite puzzled to see these gems appeared almost too good to be true. The presence of so many gas bubbles left me completely perplexed. Nothing like I had ever seen, these gems has a princely red colour and even appeared eye clean, but with a little magnification, the gas bubbles glistened under the light.
lead filled ruby
Lead Glass Filled Ruby

Quite shocked by the appearance of these stones I studied these stones a little deeper. Discussions with my colleagues and google searches later, I found out about lead filled rubies.

What is a Lead Glass Filled Ruby

A lead filled ruby like any other precious ruby, is treated to improve the colour and clarity of the gem. With the improvement in appearance, comes a big improvement in price, making these gems more marketable. Lower quality gems are placed in a crucible with a coloured lead rich glass. Once heated, the fluid glass, permeates the fractures on the gemstones and create a seal that hardens improving both quality and clarity.

Some interesting facts about these treated stones were :

  1. Gas bubbles: These stones have trapped gas bubbles that look like doughnuts under magnification.
  2. Crackled effect on surface: Visible under reflected light, you can see a different lustre. Areas filled vs areas without any filling.
  3. Colour: Can sometimes have an orangy yellowish to purplish body colour.
  4. Heated inclusions: This is because in order for the lead glass to flow into the fractures the temperature must be 700 – 900 degrees. This results in surrounding gem material to heat up causing melted fingerprints, discoid fractures etc.
lead filled ruby
Difference in lustre


lead filled rubies
Gas bubbles in the gem


lead filled rubies
Orangy to pinkish purple colour

Lead Filled Ruby