Question Summary:
Is this sinful and considered as stealing?

Question Detail:

I am working in the office and there was a big cup of tea Which was unattended for atleast a month I took it without asking anyone I did not know who this cup belongs to. All i know is that it was unattanded for a while and Could have gone into waiste Does it come in stealing Please help as i am not satisfied whether i have done the right thing or wrong ???

Answer :

 
In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
 
When you state you took the cup, do you mean merely utilizing the cup or taking it in your possession? If you meant merely using it, then if there was any indication that the owner has left the cup and wouldn’t mind anyone using the cup, then you may use the cup. If you meant taking the cup then the cup is to be considered as an amānat (entrusted item). If you have adopted reasonable means to locate the owner of the cup and you were unsuccessful and you are certain that no one would claim for the cup, you may assume ownership of the cup, provided you are a legitimate recipient of Zakāh. If you are not a legitimate recipient of Zakāt, then you may keep the cup in your custody and utilize it as you wish until the original owner shows up or give the cup away to someone who is eligible to receive Zakāt.[i]
 
And Allah Ta’āla Knows Best
Khalil Johnson
Student Darul Iftaa
Canada 
Checked and Approved by,
Mufti Ebrahim Desai.