"A stone is a small lump of rock that can be thrown by someone, eg, hypothetically, by an alleged protester at the police.I'm sure that I shall never confuse the two again. But what if someone throws a piece of Blackpool rock at the fuzz? Apart from the sticky mess it would leave on their day-glo jackets, I mean. Can we call that rock?
"In British English, a rock is too big to be thrown effectively in that way; however, chiefly in North American and Australian English, a stone that can be thrown is called a rock.
"As we aspire to British English, please make sure that we do not refer to a rock when we mean a stone."
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