Oolite

If the Oxford English Dictionary is to be believed, this word is frequently mispronounced, even by many professionals.

Don’t say ‘oo-lite’ as others might,
For ‘oh-uh-lite’ is really right.
Who says? Not me, the OED;
And who are we to disagree?

[Image (of a thin section of oolite): Wikipedia/Mark A Wilson]