The round took place in May. Other investors included angel investors Wang Lijie, Cai Wensheng and Xue Manzi.
Beijing-based Zhubao.com received its first round of financing from PreAngel Partners last October.
Shanghai Buttonwood is an angel and early stage investment firm with a focus in mobile internet, digital media and clean energy. The company previously invested in popular Chinese mobile app Momo.
Zhubao.com has about 100 online jewelry sellers selling gold, silver, diamond and jade items.