Ricky Gray robbed Christianne Douglas s store Coleman Douglas Pearls, in Beauchamp Place, Knightsbridge.
Mrs Douglas - whose clients include Helen Mirren, Julie Walters and Halle Berry - was forced into her basement where she kept her stones and valuables.
Gray ordered Mrs Douglas to fill up three large bags with pearls worth £630,000 before fleeing the scene on July 9, 2019.
In November 2012, Gray was jailed for eight years after he stole some £250,000 of diamonds from the founder of Petplan, Patsy Bloom, in a robbery at her £3.5million London home.
Ricky Gray robbed Christianne Douglas s store Coleman Douglas Pearls, in Beauchamp Place, Knightsbridge
INQUEST: Dr Nicholas Shaw has said changes need to be made An elderly woman has died of heart failure after an NHS 111 call handler wrongly assumed she was suffering from coronavirus symptoms. In September, last year, Patricia Douglas from Penrith was rushed to hospital with severe breathlessness, while at A&E she collapsed and could not be resuscitated. Dr Nicholas Shaw, assistant coroner for Cumbria, has now called for a change in the guidance after the 76-year-old failed to get the treatment she needed. An inquest report published earlier this month has revealed how Mrs Douglas called the NHS 111 service at 11.49am on Sunday, September 27 having suffered severe breathlessness.