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 :
- Gas bubbles: These stones have trapped gas bubbles that look like doughnuts under magnification.
- Crackled effect on surface: Visible under reflected light, you can see a different lustre. Areas filled vs areas without any filling.
- Colour: Can sometimes have an orangy yellowish to purplish body colour.
- 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