The difference between beryl and barrel is exactly the same.
Okay, this I don't understand, at all. Unless you pronounce barrel with the same a-sound that's in bar?
I pronounce barrel with the same a-sound that's in bare.
Beryl looks as though it ought to have the same vowel sound as berry. Just like in bare, or air.
And, sterile is STAIR-ill. Or, maybe, STAIR-ull is closer.