November 2003 – The Preservation League of New York State listed 2 Columbus Circle among its "Seven to Save" sites, prompting artist Chuck Close to write, "I have always enjoyed this distinctive and delightful building with its opaque white facades and punched out hole windows."
Despite being opaque at visible-light wavelengths, use of the Very Large Telescope at Cerro Paranal has revealed the presence of about 3,700 blocked background Milky Way stars, some 1,000 of which are visible at infrared wavelengths.
It is an amorphous, opaque, and very friable material of fawn-brown color, filling cavities in the torbanite or Boghead coal of Bathville, Lothian, Scotland.
Later sets had some transparent purple bulbs (a representation of black, similar to blacklight), a few even have transparent green, or a translucent or semi-opaque lime green (possibly representing slime as in Ghostbusters, or creatures like goblins or space aliens).
Darlexx is thicker, more constricting, and more opaque than spandex, which has led to its use in a range of fetish and bondage garments, such as hobble skirts, straitjackets, and hoods.
Edeowie glass is a slag-like, opaque rare natural glass found as vesicular or in sheet-like masses in a semi-continuous swath in baked sediment, about 55 km long and 10 km wide along the western side of the Flinders Ranges near Parachilna, South Australia and Lake Torrens.
Opaque limoncellos are the result of spontaneous emulsification, otherwise known as the Ouzo Effect, of the sugar syrup and extracted lemon oils.
Ultraviolet (UV) radiation is ionizing but it is not penetrating, so it can be shielded by thin opaque layers such as sunscreen, clothing, and protective eyewear.
The technique can be used with both translucent and opaque enamel, but more commonly the later; translucent enamel is mostly found on reliefs using ronde bosse, such as a plaque with the Entombment of Christ in the Metropolitan Museum of Art, New York.
In the infrared, this allows for measurements as low as 350 cm−1 (28 µm), whereas zinc selenide is opaque by 21.5 µm and ZnSe optics are generally only usable to 650 cm−1 (15 µm).