A bit of a jewellery question but chemistry related. I want to encase a synthetic ruby (corundum, Al2O3) in silver by melting the silver around it. Either in a furnace or by casting. The MP of silver is 960 °C.

The ruby will be facteded and polished. Now, in theory the ruby should be unharmed given that its MP is double that of the silver and is much harder. However, would there be any damage to its optical properties?

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    $\begingroup$ There could be risk of fracture or minor defects due fast and uneven temperature changes, related to the material thermal dilation. $\endgroup$
    – Poutnik
    Apr 23, 2019 at 11:52

1 Answer 1


However, would there be any damage to its optical properties?

It is almost guaranteed. Corundum is incredibly sensitive to thermal shock and unless you can do this in a furnace that heats very slowly, it will fracture/crack.

As far as any other properties, your ruby should not see any change in other optical properties for such a short duration, but for longer durations (hours at high temperature) metals can diffuse into the ruby and cause color changes, but I doubt this is an issue for what you describe.

  • $\begingroup$ So the only method would be slow heating and cooling. I shall have to try it and see what happens. Experiment rules... $\endgroup$ Apr 23, 2019 at 15:56

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