Metallic element, rather odd, gathering attention (4,5)
I believe the answer is:
rare earth
'metallic element' is the definition.
(I've seen this before)
'rather odd gathering attention' is the wordplay.
'odd' indicates anagramming the letters.
'gathering' is an insertion indicator (gather can mean to acquire or bring in).
'attention' becomes 'ear' (having someone's ear is having their attention).
'rather' is an anagram of 'rareth'.
'rareth' enclosing 'ear' is 'RARE-EARTH'.
(Other definitions for rare earth that I've seen before include "One of a group of 15 hard to distinguish elements - at her rear (anag)" , "Oxide" , "Particular element" , "element such as promethium" , "One of a particular group of metallic elements" .)