Someone who's arse is so tight (in relation to money) their shit turns to diamonds.

Originally coined in late 2001 in reference to an uber tight arsed flat mate.
What do you mean you splitting the bills into fractions of a cent? You diamond maker!
by DutchDownUnder October 1, 2006
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describes someone with an extremely tight anus, in reference to anal sex (as diamonds are created by extreme pressure)
At the sight of Ed's 9-inch dick, Bernie shockingly said "Hell to the no! I'm a diamond maker. Good luck trying to get that in!"
by JerBer_nyc September 27, 2008
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