The Collaborative International Dictionary of English v.0.48:

Rough \Rough\, a. [Compar. Rougher; superl. Roughest.] [OE.
   rou?, rou, row, rugh, ruh, AS. r?h; akin to LG. rug, D. rug,
   D. ruig, ruw, OHG. r?h, G. rauh, rauch; cf. Lith. raukas
   wrinkle, rukti to wrinkle. [root] 18. Cf. Rug, n.]
   1. Having inequalities, small ridges, or points, on the
      surface; not smooth or plain; as, a rough board; a rough
      stone; rough cloth. Specifically:
      (a) Not level; having a broken surface; uneven; -- said of
          a piece of land, or of a road. "Rough, uneven ways."
          --Shak.
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      (b) Not polished; uncut; -- said of a gem; as, a rough
          diamond.
      (c) Tossed in waves; boisterous; high; -- said of a sea or
          other piece of water.
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                More unequal than the roughest sea. --T. Burnet.
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      (d) Marked by coarseness; shaggy; ragged; disordered; --
          said of dress, appearance, or the like; as, a rough
          coat. "A visage rough." --Dryden. "Roughsatyrs."
          --Milton.
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   2. Hence, figuratively, lacking refinement, gentleness, or
      polish. Specifically:
      (a) Not courteous or kind; harsh; rude; uncivil; as, a
          rough temper.
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                A fiend, a fury, pitiless and rough. --Shak.
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                A surly boatman, rough as wayes or winds.
                                                  --Prior.
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      (b) Marked by severity or violence; harsh; hard; as, rough
          measures or actions.
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                On the rough edge of battle.      --Milton.
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                A quicker and rougher remedy.     --Clarendon.
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                Kind words prevent a good deal of that
                perverseness which rough and imperious usage
                often produces.                   --Locke.
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      (c) Loud and hoarse; offensive to the ear; harsh; grating;
          -- said of sound, voice, and the like; as, a rough
          tone; rough numbers. --Pope.
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      (d) Austere; harsh to the taste; as, rough wine.
      (e) Tempestuous; boisterous; stormy; as, rough weather; a
          rough day.
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                He stayeth his rough wind.        --Isa. xxvii.
                                                  8.
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                Time and the hour runs through the roughest day.
                                                  --Shak.
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      (f) Hastily or carelessly done; wanting finish;
          incomplete; as, a rough estimate; a rough draught.
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   Rough diamond, an uncut diamond; hence, colloquially, a
      person of intrinsic worth under a rude exterior.

   Rough and ready.
      (a) Acting with offhand promptness and efficiency. "The
          rough and ready understanding." --Lowell.
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      (b) Produced offhand. "Some rough and ready theory."
          --Tylor.
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Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "rough diamond":
   acceptable person, capital fellow, crude, diamond, gem, gentleman,
   good fellow, good lot, good man, good person, good sort,
   good woman, honest man, jewel, lady, mensch, ore, pearl,
   perfect gentleman, perfect lady, persona grata, prince,
   raw material, real man, rich ore, rich vein, right sort,
   unanalyzed mass, unlicked cub, virgin soil, worthy