http://physicsweb.org/article/news/8/8/9
Anyone seen any recent news pieces on missing whales or UFOs over San Francisco?
Neat.
On the way to work today, a little guy with a funny accent asked me where the “nuclear wessels” were kept. Man, was he lost.
bzzzzzt!
Sorry, alumina is not aluminum. The former is a rock; the latter is a metal. The former contains aluminum in an oxidized state; the latter is the elemental form of aluminum with few impurities. The former is a glass; the latter is crystalline or polycrystalline. The former is an insulator, with a very large gap between valence and conduction bands; the latter is a metal with no gap between valence and conduction bands.
Transparent alumina is not what Montgomery Scott revealed the formula to; it was transparent aluminum.
Even the editors of slashdot fell victim to this error of ignorance. :eek:
But this is The Straight Dope. 
Even if it is the Mundane part…
Admiral. There be whales here!
Hello? computer?
Just use the keyboard.
Hnh. How quaint.
Hey, now, people who live in fully crystallized alumina-rare earth oxide ceramic houses shouldn’t throw stones!
Not now Madeleine!
Out of sequence, I know, but no one can see me randomly pecking at keys and running through molecular formulas…
Technically, alumina is a mineral. Rock has a less exact (and often less uniform) chemical composition than a mineral does. Kind of a petty nitpick, but like you said this is the Straight Dope. 