Cheap marble's dull (6)

I believe the answer is:

tawdry

'cheap' is the definition.
('tawdry' can be a synonym of 'cheap')

'marble's dull' is the wordplay.
'marble' becomes 'taw' (taw is a kind of marble).
'dull' becomes 'dry' (I've seen this before).
'taw'+'dry'='TAWDRY'

(Other definitions for tawdry that I've seen before include "Showy but cheap and nasty" , "Vulgar" , "Shabbily gaudy" , "Tastelessly showy" , "Showy, cheap; sordid" .)

I've seen this clue in The Telegraph.

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