An outright blessing, this element! (5)
I believe the answer is:
boron
'an outright blessing this element' is the definition.
'boron' can be an answer for 'element' (boron is a kind of element). I'm unsure of the rest of the definition.
'blessing this element' is the wordplay.
'blessing' becomes 'boro' (I can't explain this - if you can you should believe this answer much more).
'this element' becomes 'N' (N is an example).
'boro'+'n'='BORON'
Can you help me to learn more?
(Other definitions for boron that I've seen before include "component of steel" , "element needed for steel" , "Atomic no 5" , "Non-metallic element, symbol B" , "Metalloid element, B" .)