The robbery occurred around 7:60 pm local time on Wednesday in the luxury Habor City mall in Tsim Sha Tsui.
One of the robbers wielded a knife to intimidate and dominate the staff and customers in the shop, while the other smashed the display cabinet and snatched two diamond rings, one diamond bracelet, two diamond necklaces and one diamond stone, Senior Inspector Chan Ka-ying of District Crime Squad Yau Tsim District told media at a briefing on late Wednesday night.
The two robbers, wearing caps and masks, finished the robbery in several minutes and escaped via escalators, Chan said.
Dozens of police officers searched the surrounding areas following the incident.
Chan said the police will investigate the suspects' nationality, whether they had cased the site before the robbery, and whether they had other accomplices or belong to any group.