• teft@startrek.website
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      11 months ago

      Types of corundum maybe but I think that’s a stretch. Sapphire is (usually) blue Al2O3. Ruby is red Al2O3. Transparent aluminum is Al2O27N5.

      • eestileib
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        11 months ago

        Watch faces are often colorless sapphire; I think industrially produced.

        • teft@startrek.website
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          11 months ago

          Any corundum without trace elements is colorless. Corundum with trace chemical impurities makes the gems we know. Chromium gives the red to rubies, sapphire has iron and titanium, you can get other colors using vanadium or different ratios. Gems are neat.

          • eestileib
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            11 months ago

            Ah so my watch branded the face as “sapphire” because it sounded more sellable than “corundum”?

    • sudoshakes@reddthat.com
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      11 months ago

      Aluminum oxynitride is transparent aluminum, but alpha aluminum oxide, which is also transparent, is called Corundum.

    • conrad82@lemmy.world
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      11 months ago

      My thoughts too, what makes this alloy so amazing? It seems to me that sapphire is harder, and otherwise similar use cases

      No mention/comparison to Sapphire in the article that I could see, disappointing.

      Maybe it is the sintering process that makes it interesting, could be easier to shape maybe 🤔