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Also [synthetic] sapphire [1] is just aluminium oxide. [1] https://en.wikipedia.org/wiki/Sapphire https://en.wikipedia.org/wiki/Sapphire
by danbruc 4mo ago
Also [synthetic] sapphire [1] is just aluminium oxide.
[1] https://en.wikipedia.org/wiki/Sapphire https://en.wikipedia.org/wiki/Sapphire