Colons and semi-colons

I've seen a few questions on this site relating to semi-colons, which I believe I correctly understand, but what I'm not as clear about is colons. For example:

The man ate the apple; it tasted good.

Is this not correctly also written as:

The man ate the apple: it tasted good.

In this case, what is the difference between the two sentences?

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Just for kicks this is a humourous approach to the semicolon: theoatmeal.com/comics/semicolon , and it's accurate too. – John K Aug 18 '10 at 5:02
"Here is a lesson in creative writing. First rule: Do not use semicolons. They are transvestite hermaphrodites representing absolutely nothing. All they do is show you've been to college." ~ Kurt Vonnegut, A Man without a Country – jcarmody Oct 27 '10 at 16:24

In your example, the first one is correct but the second one is incorrect.

Use a semi-colon to connect two related independent clauses.

They took the money from the vault; they took it quickly.

The ideas are related, the clauses stand on their own, semi-colon is OK here.

Use a colon to separate equal things (like an '=' sign).

Just remember three things: be on time, bring the money, and come alone.

The things here = those three items.

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Colon is a punctuation mark indicating

• that a writer is introducing a quotation or a list of items.
• that a writer is separating two clauses of which the second expands or illustrates the first.
• a statement of proportion between two numbers: a ratio of 10:1.
• the separation of hours from minutes (and minutes from seconds) in a statement of time given in numbers: 4:30 p.m.
• the number of the chapter and verse respectively in biblical references: Exodus 3:2.

Semicolon is a punctuation mark indicating a pause, typically between two main clauses, that is more pronounced than that indicated by a comma.

In your example, the colon is not what I would use.

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A semicolon isn't used to indicate a pause; it's used to indicate that two independent clauses are closely related to each other. The pause is just how it manifests itself in speech. – mipadi Aug 17 '10 at 21:55
Your second bullet point says: "the second expands of illustrates the first". Is that not exactly what my example above was doing ? – pm_2 Aug 18 '10 at 6:25
@pm_2: See how I used the colon in the description for colon. The sentence you wrote is normally written using a semicolon; I have never seen anybody using colons in such cases. – kiamlaluno Aug 18 '10 at 15:32
It seems there's a grey area between using a colon to indicate that the second sentence is expanding on the first, and using a semicolon to indicate that the two sentences are related. Could someone clarify? – Seamus Sep 3 '10 at 16:24
@Seamus, yes, there is definitely a grey area in usage. For some writers, one is preferable over the other; for others, they would use neither. And for still others, it is a creative choice. – staticsan Feb 24 '11 at 0:45

Both can be correct. It depends on quite what you are intending to convey and the context surrounding the statement.

The first one shows two coupled actions with equal priority in the narrative. The semi-colon couples them closer than if they were two sentences, but the comparative effect depends strongly on the surrounding text, such as where they are in the paragraph, how big or small the paragraph is, and what else is being described.

The second example, using the colon, shows a more direct relationship between the clauses. They are not equal in this construct, but dependant. The second clause is the focus of the sentence, but again, the effect still depends on the surrounding text. Your second example would work well at the end of a passage where the apple is an important item and that it tasted good was a satisfying resolution.

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