Online jewelry stores can offer lower prices because they don't have to pay rent and endure other expenses that shops at malls have to. They tend to have larger inventories and a better selection.

At DiamondXcellence.com:

• You can shop at your leisure without the pressure of sales people.
• You can comparison shop without having to worry what others think of you.
• You can take an online price and go to a jeweler in person and haggle a price further down.
• If the piece is incredibly inexpensive and you can't imagine how you got such a deal, you're being cheated. Don't buy it.
• Gemstones need to be appraised and certified by some objective criteria. Given this, their prices are fairly standardized. If something is much less expensive than similar items, it's of a lower quality.