Three masked men dressed in dark clothing smashed through the Hamilton and Inches jewellery store in George Street, Edinburgh, at around 11.30am on Friday, June 6, rounded up staff and threatened them with an axe, a hammer and a machete.
They smashed a number of display cabinets before making off with goods including a £325,000 diamond Chatila necklace and eight Patek Phillipe watches ranging from £22,000 to £66,000.
All the suspects made off in a white BMW with a waiting driver which was abandoned in Gloucester Lane before getting into a dark blue Honda CRV, seen heading towards Stockbridge.
The Honda, a late 2007 model, is thought to have travelled along Gloucester Street on to Kerr Street, then towards Raeburn Place.
The second car was abandoned in a car park at East Pilton Farm Rigg, in Edinburgh.
Dave Hunter, senior regional manager for Crimestoppers, said: "We would urge anyone with information to contact us anonymously, safe in the knowledge that their identity will not be revealed."