### Clue: Necklace of gold kept by the Celts, primarily (4)
### Answer: TORC 
 ### Explanation: Definition: Necklace
 OR(the colour of gold in heraldry) **contained in**(kept by) **the 1st letters, respectively, of**(…, primarily) "the Celts ".
Defn: … worn by the ancient Gauls and Celts.