So it sells a ton in 10 days (two weeks?), that's 26 tons a year.
How many such stores are doing similar businesses? It's an easy few hundred tons of demand a year for the whole of China.
China produces about 340 tons a year I think. And I reckon China's domestic gold production probably is totally absorbed by the Chinese central bank so the retail demand have to be met from import.
And I know for a fact that Chinese people do not sell gold, the real physical gold unless been put in a severe financial hardship. They are hoarders like the Indian people.