Gemstone from Saxony tossed across road (8)
I believe the answer is:
Here is my best explanation:
'gemstone' is the definition.
(sardonyx is a kind of gemstone)
'saxony tossed across road' is the wordplay.
'tossed' indicates an anagram.
'across' indicates putting letters inside.
'road' becomes 'rd' (abbreviation).
'saxony' anagrammed gives 'saonyx'.
'saonyx' placed around 'rd' is 'SARDONYX'.
'from' is the link.