Lost my grandmother's diamond necklace

Lost a small black velvet jewelry bag I think on the C train between Rockaway Ave and Utica Ave, or at the Utica Ave station while I was transferring to the A. It contained two gold flower rings, two pairs of gold hoops, and a thin gold chain with three diamonds on it that was made from my grandma's ring. It is the only possession I have of hers. I know it's a long shot but if found please give to a conductor or station attendant. Thank you.