As in the following:
A common proverb is: “A rolling stone gathers no moss.”
A common proverb is: “A rolling stone gathers no moss”.
A common proverb is: “A rolling stone gathers no moss.”.
If the proverb weren't a full sentence, I would immediately put a single period after the quote, at the very end. But if it is a sentence, which period should be removed so that there is only one period? Two periods look absolutely dorky.
Like all comprehensive answers about English (or those attempting to be so), this answer begins with, “it depends”.
A quotation that is not a complete statement should never have a period within its quotation marks:
The senator, when asked why he refused to support the measure, said that the language of the bill was “confusing and verbose”.
“Confusing and verbose” is not a complete statement; the quotation is simply attributing these exact words to the senator, while summarizing his complete statement largely through omission.
By contrast, a more complete statement attributed to the senator CAN have the period inside the quotes:
The senator, when asked why he refused to support the measure, said: “The American people deserve to understand the laws their representatives in Congress are writing, and this confusing and verbose bill hinders that effort.”
Now, it is still acceptable to place the period outside the quotation marks in this case. However, if the quotation spans the entire sentence from capital letter to fullstop, and/or continues for multiple sentences and comprises a full paragraph, the quotation should enclose the final period.
In American English, commas and periods are placed inside the quotation marks. Therefore, the following one is how the sentence is written in American English.
A common proverb is, “A rolling stone gathers no moss.”
The period is placed inside the quotation marks even if it’s not part of the quoted phrase, and it is written only once. The period is placed inside the quotation mark even if the part between the quotation marks is not a complete sentence.
The word “punctuation” derives from two ancient roots: “punc,” meaning “a hoodlum,” and “tuation,” meaning “desire to become.”
(The etymology is false; it’s just a funny example taken from Comma sense: a fun-damental guide to punctuation, written by Richard Lederer and John Shore.)
Just to complete the information, these are other examples of punctuation used with quotation marks.
I confessed, “I love punctuation”; then I explained “I also love spelling rules.”
“Punctuation”: Ah, how that word makes my heart thump.
I asked, “Do you think I love punctuation?”
How wonderful that I can finally confess “I love punctuation”!
As far as I know, in British English the sentence is written as follows:
A common proverb is “A rolling stone gathers no moss”.
You're really looking at a corner case of convention and I would suggest:
If you look at what authors tend to do in the usual case, you'll see that they put the stop inside the quotation marks when it's a whole sentence uttered by a particular person (or quoted from a particular text) where that quotation essentially 'stands on its own' as a sentnce, possibly barring tags such as "He said". And many authors wouldn't double up stops (so even if you'd logically expect a double stop, one cancels the other out). But you'll also find style guides (including Fowler, for what it's worth) advocating the doubling of the stop.
So it boils partially down to whether you think a proverb is a "quotation standing on its own". You could argue yourself into knots one way or another. And it boils partially down to which convention/author's precedent you want to follow. You could argue yourself into knots about which convention to choose.
So as I say, I would really just do what you think looks clear and logical unless a "power that be" is really stipulating to you one way or another.
From what I'm used to and believe to be the proper way, this is the correct option:
A common proverb is: "A rolling stone gathers no moss."
Anyone agrees?
