It's found in salt and mud, so I worked out (6)
I believe the answer is:
sodium
'it's found in salt' is the definition.
I can't judge whether this defines the answer.
'mud so i worked out' is the wordplay.
'worked out' indicates anagramming the letters.
'mud'+'so'+'i'='mudsoi'
'mudsoi' anagrammed gives 'SODIUM'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for sodium that I've seen before include "Chemical in salt" , "Metal present in common salt" , "Metal found in salt water, Na" , "1 down, symbol Na" , "Element in table salt" .)