https://en.m.wikipedia.org/wiki/Aluminium_oxynitride

I'm pretty sure it is actually a thing that can be made. Presumably not very efficiently though as we don't see it all that much.

sapphire?

Came for this, thanks for doing it for me.

It's fine, I've heard wangs are rising as well.

The plot of the fourth movie, Star Trek IV: The Voyage Home, is a slightly off the wall plot.

A giant alien space probe arrives in orbit of Earth making weird noises, it sucks up all the power from ships in orbit and power grids on the surface and starts evaporating the oceans. Turns out it wants to talk to humpback whales, which in this timeline were hunted to extinction in the 20th century, so there are no humpback whales on earth for the probe to talk to, and it's literally tearing up the oceans to find them.

Meanwhile, Kirk and his crew of main characters are on Vulcan (Spock's home planet) in possession of a stolen Klingon warship which they've been preparing for the flight back to Earth to face court martial, because of the events of the previous movie. They learn of the problem before they reach Earth, they figure out that the probe wants to talk to whales. "can we pretend to be whales?" "we can make the sounds, but we don't speak the language." So they just casually decide to time travel by doing a high speed lap of the sun. No shit they just fly really fast around the sun and arrive in the 1980's, where it just so happens the Bay Aquarium has a breeding pair of captive humpback whales on display. Meanwhile, the trip through time ran them out of fuel. Cue a LucasArts style multi-problem plot where they have to figure out how to refuel their ship, modify it to carry humpback whales, find and acquire the whales, and then get back to the future.

Spoiler alert: They do. They crash their ship into 23rd century San Fransisco bay and release the whales, which do this whole new age thing with the probe, which then goes "Understandable, have a nice day" sucks in its volleyball and floats away. Then that court martial scene which is actually part of the previous movie not this one ensues, where Kirk is punished with a reward.

TL;DR the main plot of the fourth movie involves the Enterprise's crew, but not the Enterprise, going back in time to bring humpback whales back from extinction.

Buddy hasn't seen the one with the whales

In one of the movies there is an alien spaceship that wants to communicate with the whales except they're all extinct, for some reason the lack of the whales is causing all of the ships to shut, so the crew have to travel back in time to the 20th century to get a whale for the alien ship to communicate with.

Yeah that was the plot, the original Star Trek movies were kind of bad really.

They discussed their plight a lot in Star Trek IV. Some relevant quotes and context here: https://memory-alpha.fandom.com/wiki/Whale

Did you have a whale of a time?

"why be happy about good things when bad things can still happen?" - the voice of trauma

Yea, who would trust a psi-cop

"Cetacean ops" is the name of the section.

Also, even ships much smaller than the Galaxy-class have it, too. It's shown on-screen in Lower Decks!

The future is now, old man