Remember Star Trek: The Voyage Home, where Scotty talks into a computer mouse and then instantly figures out keyboards and gives away the formula for transparent Aluminum? And remember Galaxy Quest, where Commander Taggart tells the Justin Long character about the ship: "IT'S REAL!"
Mash those two scenes together and you have Spinel, described by US Naval Research Laboratory scientist Dr. Jas Sanghera as "actually a mineral, it's magnesium aluminate. The advantage is it's so much tougher, stronger, harder than glass. It provides better protection in more hostile environments—so it can withstand sand and rain erosion." He likes it for the same reason Scotty did, according to an NRL press release:
As a more durable material, a thinner layer of spinel can give better performance than glass. "For weight-sensitive platforms-UAVs [unmanned autonomous vehicles], head-mounted face shields—it's a game-changing technology."
The spinel is made by sintering. Sanghera describes it:
"You put the powder in [a hot press], you press it under vacuum, squash this powder together—and if you can do that right, then you can get rid of all the entrapped air, and all of a sudden it comes out of there clear-looking."
After the sheet comes out of the press, it has to be ground and polished, an expensive process for a material that is so hard. But when the cost comes down there will be lots of uses, from the obvious military ones like bulletproof glass, to the consumer applications like smart phones and watches. There is also a commercial version called ALON made in monolithic windows up to 18" x 35".
In a trade magazine, Glass Canada, (the source for this article) the editor notes the architectural uses that might happen when the cost drops, including glass balconies that don't explode and truly fire-resistant glass.
And of course, making big tanks for George and Gracie.