If loss can occur, is stony (6)
I believe the answer is:
fossil
'occur is stony' is the definition.
I can't judge whether this definition defines the answer.
'if loss can' is the wordplay.
'can' is an anagram indicator (I've seen 'canned' mean this (canned can mean drunk)).
'if'+'loss'='ifloss'
'ifloss' is an anagram of 'FOSSIL'.
Can you help me to learn more?
(Other definitions for fossil that I've seen before include "Very old relic - outdated person" , "Fogeyish old thing" , "Ancient remnant hardened in rock" , "Antiquated person" , "amber, say" .)