Two robbers armed with knives headbutted a shopkeeper before stealing cash, cigarettes and his cherished gold chain.
The shop, Saffron Newsagents, in Saffron Lane, Leicester, was targeted at 6pm on Monday.
The two robbers, who are thought to be aged 16 to 18, threatened the shopkeeper with their knives before one of them headbutted him.
They then stole cash from the till, cigarettes and the man's Samsung Galaxy 2 phone.
Before leaving, one of them grabbed a 24-carat gold chain from the man. The chain had a heart-shaped locket decorated with three diamonds attached to it.
Detective Constable Jenny Tattersall is investigating the incident, he said: "This was a frightening incident for the victim who has been left devastated by the theft of his chain which is of great sentimental value to him.
"If you witnessed the incident or you saw two men acting in the Saffron Lane area on Monday evening we would urge you to contact the police.
"Any calls received will be treated in confidence."
The men are both white, slim and approximately 5ft 6in.
One was wearing a black tracksuit, black gloves and a blue bandana, which was covering his nose and mouth.
The second attacker was wearing a black tracksuit, black gloves and a red bandana.
Contact Det Con Tattersall on 101 or Crimestoppers, which is anonymous, on 0800 555 111.
