An odd piece of virtu to us (7)
I believe the answer is:
curious
'an odd' is the definition.
(I've seen this before)
'piece of virtu to us' is the wordplay.
'piece of virtu' becomes 'curio' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'curio'+'us'='CURIOUS'
Can you help me to learn more?
(Other definitions for curious that I've seen before include "Odd, peculiar" , "Strange, unusual" , "Eager to learn, strange" , "Questioning" , "Odd or eager to know" .)