Beam me up, Scotty - it exists. (Apparently, I live under a rock and missed this until today.)
It’s technically Aluminium oxynitride. It definitely has interesting and useful properties.
Yay! Now I can finally have that pet whale I’ve been yearning for!
If you are going to count compounds containing aluminum, then you have Gorilla Glass and sapphire glass.
Very cool!
So not aluminum. Just like optically transparent sapphire isn’t transparent aluminum. It’s alpha-alumina. This is like calling water “liquid oxygen you can drink!”
Actually, “liquid hydrogen you can drink” sounds more impressive.
A nice tall glass of liquid hydrogen. Yum.
Way cool. I got my official communicator a while back. Now with this real phasers and transporters can’t be far behind.
I was fascinated when I first read this. I read up on the substance and realized that it had in fact been invented back in the 70s and is still under patent to one company. Clearly a commercial product and clearly the owners have decided that low sales works for them. Otherwise we would have it in everyone’s car windows by now! 
As I gather from reading, one basic limitation is that it is so hard it is difficult to polish properly-raising it’s costs.
Again, a compound that contains aluminum is not “transparent aluminum.” And if it is, then the aluminosilicate Gorilla Glass on millions of cell phones is “transparent aluminum” and the sapphire on some Apple devices is “transparent aluminum.”
Right. Those are other examples of transparent aluminum. What’s your problem with this? There’s a aluminum in it and you can see through it, it’s transparent aluminum.
“Whose to say he didn’t invent the thing?”
According to Memory-Alpha, the transparent aluminum described in Star Trek is apparently a compound consisting of hydrogen, accurentum (or perhaps actinium) and aluminum.
Isn’t water actually hydrogen ash?
Hydrogen rust.
Something that has always bothered me about the film: why was it so important that the walls of the whale tank were transparent? It was so important that Scotty was willing to change history and give out the formula for transparent aluminium.
Why not just make it out of regular opaque aluminium?
Whales are intelligent. Would you want to be locked in a pitch dark cage? It’s doubtful any lights are waterproof.
I thought that the point was that they needed a very strong but lightweight material–and “transparent aluminum” is spacy-sounding gibberish, like “dilithum.”
No need for a roof, just rig up some Klingon floodlights above the tank. The whales weren’t in there very long.
I always thought it was a very silly aspect of the story: Fish tanks are always see-through, therefore it’s absolutely critical that this emergency tank inside the Bird of Prey absolutely must be see-through too. Weird.
Think about it. A critical moment of dialogue depended UTTERLY on the transparency of the tank walls.
It just doesn’t work if Scotty can’t see into the tank. “Admiral, I think there be whales here. Yaar.”
The tank had to be transparent; otherwise (A) you don’t get to see a nice CG transporter effect, and (B) Scotty has to say something not inane.