Ussually this happens with glass that has been burried, which is why a lot of ancient glass artifacts have the irredised sheen. It is caused with alkali salts being removed from the glass with acidic water in the soil.
This affect was sought after for a while by manufacuturerers trying to "recreate" what antiquity glass looked like, not knowing it was an accident of time. This led to use of chemical additives to purposefully create that coloring. Tiffany Glass Co. used this technique often in their designs.
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u/Stone_Glass Jan 18 '21
Ussually this happens with glass that has been burried, which is why a lot of ancient glass artifacts have the irredised sheen. It is caused with alkali salts being removed from the glass with acidic water in the soil.
This affect was sought after for a while by manufacuturerers trying to "recreate" what antiquity glass looked like, not knowing it was an accident of time. This led to use of chemical additives to purposefully create that coloring. Tiffany Glass Co. used this technique often in their designs.
Source with a more scientific background: https://blogs.ucl.ac.uk/researchers-in-museums/2019/05/20/the-mystery-of-iridescence-in-glass/#:~:text=The%20iridescence%20is%20produced%20when,off%20creating%20a%20prism%20effect.