Crossword Genius

Stone put underground, shifting the odd bits around (4)

Ross

I believe the answer is:

ruby

'stone' is the definition.
(I know that ruby is a type of transparent gem)

I don't understand how the rest of the clue works.

(Other definitions for ruby that I've seen before include "killed an assassin" , "Deep red variety of corundum" , "A red jewel" , "Jack perhaps" , "Vivid red" .)

I've seen this clue in The Independent.
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