Re-hosting this question from Physics to Chemistry, lightly edited.

Rubies and sapphires are chemically equivalent to the mineral corundum, with the exception of transition metal impurities that impart different colors to the aluminium oxide. Uranium is not a transition metal, but it can be used as a coloration admixture with silicon dioxide, and exists in various oxide forms.

Can uranium be used as a coloration impurity for 1) aluminium oxide based gemstones and/or 2) diamonds? If uranium cannot chemically bond with the substrate, then the ability to produce a consistent heterogeneous mixture, e.g. by suspending uranium oxide dust in molten aluminium oxide during the process of flame fusion would be a satisfactory answer in the affirmative.

  • 1
    $\begingroup$ Cross-posting is frowned upon, though... $\endgroup$
    – Mithoron
    Jun 1 at 20:32
  • 2
    $\begingroup$ @Mithoron A mod over at physics suggested here might be better. I see no reason, a priori, it would not be possible to dope the alumina with urania, in moderation. Maybe the result would not be transparent, like uranium glass? $\endgroup$
    – Ed V
    Jun 1 at 21:01
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    $\begingroup$ @EdV Yeah, but migration would be proper way to solve it. BTW Uranium is way bigger then Al and that may be a problem. $\endgroup$
    – Mithoron
    Jun 1 at 21:38
  • $\begingroup$ This actually sounds like an interesting concept. Even if it isn't as easy as it would be for some smaller transition metals, at low concentration is might be interesting. And easy to test. $\endgroup$
    – matt_black
    Jun 1 at 21:43
  • $\begingroup$ @Mithoron Agreed on both points. Still, it would be interesting to see what happens with a low doping level. $\endgroup$
    – Ed V
    Jun 1 at 22:14

1 Answer 1


It's not quite alumina, but uranium(VI) oxide compounds have been used to color glass:

Oxides and uranates of uranium(VI) have been used in the past as yellow ceramic glazes as in Fiesta and to make yellow-green uranium glass.1

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But beware:

Both of these applications are abandoned due to concern regarding radioactivity of the uranium.

Cited Reference

  1. Skelcher, Barrie (2002). The Big Book of Vaseline Glass. Atglen, PA: Schiffer Publishing. ISBN 978-0-7643-1474-2.

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