Loyal friend starts to act tearful, consumed by feelings of tenderness (7)
I believe the answer is:
achates
'loyal friend' is the definition.
(I've seen this before)
'starts to act tearful consumed by feelings of tenderness' is the wordplay.
'starts to' indicates taking the first letters.
'consumed by' indicates putting letters inside (inserted letters get consumed).
'feelings of tenderness' becomes 'aches' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The initial letters of 'act tearful' is 'at'.
'at' put within 'aches' is 'ACHATES'.
Can you help me to learn more?
(Other definitions for achates that I've seen before include "faithful companion" , "Exemplary" , "Trusty comrade" , "trusted comrade" , "Loyal supporter" .)