I recently bought some 0.1 carat lab grown CVD diamonds online. I am trying to figure out a method of escrow to buy a 2 carat CVD lab grown diamond from the sam

I recently bought some 0.1 carat lab grown CVD diamonds online. I am trying to figure out a method of escrow to buy a 2 carat CVD lab grown diamond from the same people for an engagement ring. To us it is actually more interesting that the diamond is lab grown copy of a natural diamon and it is proof of human ingenuity and work to me.