A Durban domestic worker allegedly stole a R50000 diamond ring from her employer and sold it for just R200 to a gold exchange company.

The 26-year-old woman was arrested on Friday and will appear in court on a theft charge this morning while her devastated Assagay employer continues her search for the family heirloom.

But private investigator Brad Nathanson, who made the arrest, believes the ring is "long gone".

The domestic worker became the prime suspect about a week ago when she crumbled under Nathanson's questioning, a day after he was hired to find a ring passed down three generations.

"The owner is absolutely devastated as she had planned to share it with her two daughters when they got married.

"The ring had three diamonds on it, and she had taken one out and reset it on a ring for herself and had kept the other two for her daughters," he said.

The employer had put on the ring and admired it before hiding it in a stuffed animal on her dressing table.

Two days later it was gone and Nathanson was hired to quiz her domestic worker.

Nathanson explained that the domestic worker led him to a gold exchange company in Pinetown.

"When I got there I found a very dodgy room with just a chair and desk. The owner did not keep a register of items brought in but was distributing pamphlets with pictures of Rolex watches and Krugerrands. After questioning the owner, I realised it was now a case of 'he said, she said'," Nathanson said.

Four months ago, a Johannesburg couple appeared before the CCMA to answer charges of failing to pay their domestic worker, fired after an argument during which she denied stealing their belongings. In February, her Whatsapp profile picture caught their eye. She was striking a pose dressed in a dress and sunglasses stolen from them.