Transparent aluminum:
Star Trek technical manuals indicate that transparent aluminum is used in various fittings in starships, including exterior ship portals and windows. It was notably mentioned in the 1986 film Star Trek IV: The Voyage Home. Panels of ultra-thick acrylic glass were needed to construct water tanks within their ship's cargo bay for containing two humpback whales and tons of water. However, the Enterprise crew, without money appropriate to the period, found it necessary to barter for the required materials. Chief Engineer Scott exchanged the chemical formula for transparent aluminum for several sheets of an adequate substitute from a manufacturer called Plexicorp. When Dr. McCoy castigates him for potentially disrupting the timeline, the engineer responds "How do we know he didn't invent the thing?" (In the novelization of the film, Scotty is aware that Nichols was its "inventor", and concludes that his giving of the formula is a predestination paradox.) The substance is described as being as transparent as glass while possessing the strength and density of high-grade aluminum. André Bormanis has concluded that the material would not be a good conductor of electricity.
The fictional term is now being used as a real world descriptor for a newly discovered transient state of matter, "transparent aluminum" which is regular aluminum bombarded with high levels of x-ray radiation, which temporarily becomes transparent to some UV radiation. It was discovered in DESY research center.[1][2]
Aluminium oxynitride is a form of ceramic whose properties are similar to those of the fictional substance seen in Star Trek.