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The optical clarity of of colorless sapphire stone and its unique refraction of light and strength for example, is not comparable to the clarity, etc. of amorphous/glass laminates.

wristexpert
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    I think military canopies are all acrylic or polycarbonate. They're tough and relatively easy to manufacture. – atc_ceedee Jul 17 '21 at 17:34
  • See this answer? https://aviation.stackexchange.com/questions/21802/what-kinds-of-materials-are-used-for-fighter-jets-glass-windshields – atc_ceedee Jul 17 '21 at 17:35
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    If a combat plane has a windshield, it'll be of laminated armour glass, similar to the glass used in an armoured trucks. – John K Jul 17 '21 at 18:28
  • "Not comparable" meaning much better, or much worse? – Ralph J Jul 17 '21 at 20:13
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    Sapphire(which is basically aluminum oxide with impurities that give it a blue color) wouldn't be used for windows, since it doesn't occur in large enough pieces, and the impurities give it color. (Many other gemstones are also aluminum oxide, with different impurities. If it doesn't have the right impurities, it's not sapphire.) Fused aluminia (manufactured) is available, but I think fused quartz is more common. IIRC, the Space Shuttle's windows were made of it. – jamesqf Jul 18 '21 at 04:22
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    Synthetic sapphire is used for the the front of the iPhone, I'm no aware of any factory manufaturing large enough pieces for use as airplane windows. – Jasen Jul 18 '21 at 12:36
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    @Jasen The iPhone uses Gorilla Glass for the screen. It only uses synthetic sapphire on its back camera lenses. – Eric S Jul 18 '21 at 14:22
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    @Jasen: It's not "synthetic sapphire", whatever lies Apple's marketing division may tell. It's fused alumina. – jamesqf Jul 18 '21 at 17:04
  • "The front windscreen and canopy [of an A-10] are resistant to small arms fire." https://en.wikipedia.org/wiki/Fairchild_Republic_A-10_Thunderbolt_II - "the canopy and windows [of an Apache] are otherwise unrated against ballistic threats." https://en.wikipedia.org/wiki/Boeing_AH-64_Apache - for some reason I always remember being told they were cultured sapphire.... Not getting shot at in a Apache is part of its charm, just like getting shot in an A-10 is. – Mazura Sep 14 '23 at 01:44

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