The retailer's official holiday shopping event will run from Nov. 29 to Dec. 2. Here's what shoppers need to know for saving ...

This selection of gems from Ouro Prêto, Brazil, and Russia's Ural Mountains, displays the golden orange to pinkish red color range of precious topaz. The gems range from 7.61 to 14.33 carats in size.

But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder than gems in the corundum family.