Sydney: A diamond ring worth half-a-million dollars was stolen from an auction site in Australia, media reported Sunday.

The pink argyle and white diamond ring, valued at 577,000 Australian dollars ($500,000), was stolen from a display counter at Theodore Bruce Auctions on Ralph Street in New South Wales, Sydney Morning Herald reported.

It's estimated around 100 people walked through the auction centre during that time.

An attendant at the auction site found that the ring was missing and immediately contacted police.

The case is under investigation. The police will inspect the CCTV cameras for clues. The organizers are amazed at the robbery as they had arranged for tight security around the ring site.