Diamond ring series. Chow Tai Fook stipulates that Chow Tai Fook's blue box is a diamond ring series. Chow Tai Fook Jewellery and Gold Co., Ltd. was established in 1929, and is a reputable jewelry company. In 1960s, Chow Tai Fook was taken over by Zheng Yutong. Later, his 999.9 pure gold jewelry became a model of the gold jewelry industry.