But remember, that manners must adorn knowledge, and smooth its way through the world. Like a great rough diamond, it may do very well in a closet by way of curiosity, and also for its intrinsic value; but it will never be worn, nor shine, if it is not polished.

Lord Chesterfield (1694-1773) English statesman, wit [Philip Dormer Stanhope]

Letter to his son, #155 (1 Jul 1748)
    (Source)