Silica ring linked to mounted circuit (4)
I believe the answer is:
opal
'silica' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'ring linked to mounted circuit' is the wordplay.
'ring' becomes 'O' (letter resembling a ring).
'linked to' says to put letters next to each other.
'mounted' says the letters should be written backwards (in a down clue, letters mounted up).
'circuit' becomes 'lap' (synonyms).
'lap' in reverse letter order is 'pal'.
'o'+'pal'='OPAL'
Can you help me to learn more?
(Other definitions for opal that I've seen before include "Mineral, usually iridescent" , "Semi-precious stone of milky or bluish colour" , "Precious stone" , "Gem stone" , "Birthstone for October" .)