Quick and Easy Buying Guide
Carat weight: 1 carat = 200 milligrams = 6.5 mm diameter. Doubling weight doesn't double diameter.
Diamond clarity: FL/IF/VVS/VS = super expensive, near perfect. SI = best value if you can check a photo for obvious inclusions (defects).
Color: D-G = colorless, expensive, only if you have money to burn. H-J = best value. Can go lower in gold metal settings than white metal.
Cut: Better cut ratings let more light into a diamond, making it sparkle more. Very important property, don't skimp here.
Set a budget and minimum cut (Premium). Go J color for gold and I/H for white metals. Go searching for SI1/SI2 clarity diamonds at James Allen. Pick a diamond with small/no inclusions. Choose a ring setting and buy it risk-free (60-day returns).
1.05 Carat Actual Size
This page provides an illustrated example presenting the actual size of a 1.05 carat diamond when set in a ring and put on a typical woman's hand. If you are hesitant to put too much stock in a simple picture, what you can do is measure the size of your finger and compare it to the 6.6 mm average diameter for a diamond of size 1.05 carats. Be aware that image such as this one are limited in what they can show - female hand sizes can vary hugely. The "first impressions" size of a diamond depends heavily on what it is shown against - her hand - a petite hand will cause the diamond to appear proportionately larger and vice versa.