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).
2.40 Carat Diamond Actual Size
This page gives a photo example presenting the actual size of a 2.40 carat diamond on an average woman's hand. Try to use the 8.8 mm mean diameter for this 2.40 carat diamond by measuring the size of your own finger in order to get an appreciation of what a diamond of this size will look like on your finger. The ring shown in the image is an average-sized size six ring; of course, the ring you get could be much larger or smaller than this one. It is good to be cautious when looking at a picture - it can't be completely representative of all finger and hand types - you are best off getting an idea in store with an actual ring. The apparent size of the diamond and ring can be affected by whether you have thick or thin digits, and also depends on their length.