Igneous material at lab's melted (6)
I believe the answer is:
basalt
'igneous material' is the definition.
'basalt' can be an answer for 'material' (basalt is a kind of material). I'm not sure about the 'igneous' bit.
'at lab's melted' is the wordplay.
'melted' indicates an anagram.
'at'+'labs'='atlabs'
'atlabs' with letters rearranged gives 'BASALT'.
Can you help me to learn more?
(Other definitions for basalt that I've seen before include "Dark fine-grained volcanic rock" , "Common volcanic rock" , "Rock containing olivine" , "rock from 2 [VOLCANO]" , "Dark rock of volcanic origin" .)