please help with this chinese chop mark thank you so much for your help....

hi this is another estate collection piece that I am trying to identify, if you have any information I would appreciate your time and thoughts. This is a beautiful spoon, bowl and plate matching hand painted set with gorgeous colors. There is a sandy grit like material that appears to be original and old. The estate said this was a qiianlong mark but I am clueless on pieces like this and would love to get feedback if you have time, many thanks again, aly