Actual Size of 1.53 Carat Diamond
This page gives a photo example of the actual size of a 1.53 carat diamond when set in a ring and put on a typical woman's hand. I have used the average engagement ring size, a size six, in the image; this ring size has an internal diameter of 0.65 inches of 16.5 mm. The hand of the woman shown in the picture has quite long and slender fingers - your fingers may or may not be similar - if they're not, be aware that a diamond engagement ring may present quite differently on your finger.
Do not forget to take into account not just the overall size of your hand, but in addition if you possess long and thin digits or squatter ones.
Compare the size of the woman's hand and the man's hand in the illustration - you can see that the woman's hand is significantly smaller and more petite (which is usually the case), so the diamond appears larger on her hand than it would obviously on his hand.