Save up to $700 off Diamonds at BlueNile.com via code 12DIAMONDS through 12/23. Plus, all custom orders placed before 12/21 are guaranteed delivery by Christmas eve. Note that this code is only valid on loose diamonds and Build Your Own Diamond jewelry purchases of $1000 or more. Spend up to $4999 and get $100 off, or get $300 off $5000-7499, or spend $7500 or more and get $700 off. There are over 70,000 diamonds to choose from, which can be searched by clarity, color, cut, carat, price, and shape. There is no sales tax (except WA and NY).