State combined with Latin about one metal (7)
I believe the answer is:
calcium
'metal' is the definition.
(I know that calcium is a type of metal)
'state combined with latin about one' is the wordplay.
'state' becomes 'ca' (abbreviation for California).
'combined' becomes 'um' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'latin' becomes 'l'.
'about one' becomes 'ci' (I've seen this in other clues).
'l'+'ci'='lci'
'um' put after 'lci' is 'lcium'.
'ca'+'lcium'='CALCIUM'
Can you help me to learn more?
(Other definitions for calcium that I've seen before include "Bone constituent" , "Element in chalk, milk" , "White metallic element in limestone, chalk" , "White metallic element found in most animals and plants, Ca" , "metal" .)