AU750 means that the material of your ring is 18K gold, which is 75 purity gold; MJ should be the abbreviation of the manufacturer or merchant; 1.064 grams should be the weight of the ring. The price of 18K gold jewelry is less than 200 per gram. If it is craft gold/color gold, it will be around 300 per gram. However, the selling point of K gold jewelry is the craftsmanship and style. They are sold by pieces. The average ring is 500~ 800 has some room for choice. There is no question of whether this thing is expensive or not, it mainly depends on whether you like the craftsmanship.

MJ "Chow Tai Fook" trademark