Sort of rock, belting out half-ugly noise (7)
I believe the answer is:
igneous
'sort of rock' is the definition.
(igneous rock is a kind of rock)
'out half-ugly noise' is the wordplay.
'out' indicates an anagram.
'half' suggests halving the letters.
'ugly' with half the letters taken is 'ug'.
'ug'+'noise'='ugnoise'
'ugnoise' with letters rearranged gives 'IGNEOUS'.
'belting' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for igneous that I've seen before include "(Rock) of volcanic origin" , "produced by fire" , "Like fire - type of rock" , "Category of rock, being of solidified molten magma" , "Of fire, like rocks formed from molten material" .)