Some mislabelled piece of stone? (4)
I believe the answer is:
slab
'piece of stone?' is the definition.
'slab' can be an answer for 'piece' (I have seen 'Piece of paving' mean 'slab' so perhaps 'piece' could also mean 'slab'). I am not sure about the 'of stone?' bit.
'some mislabelled' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'SLAB' is hidden within 'mislabelled'.
Can you help me to learn more?
(Other definitions for slab that I've seen before include "Broad, thick piece of wood, stone" , "24 tinnies [STRINE] < in a wooden hut [STRINE]" , "Paving stone" , "Hunk" , "Piece, e.g. of cake" .)