Wow, what a fine matched pair! Just exceptionally cut stones. Natural stones. All Blue Topaz are heated and irradiated to get their color. This is an industry accepted standard applied to all Blue Topaz. Most gemstones bought online aren't very high quality. They're generally poorly cut, have weak color and too many inclusions. In order for a gemstone to qualify as jewelry grade, it has to meet all three of those quality standards -- cut, color and clarity. This gemstone is jewelry grade, and is ready to be used as the center stone for a piece of high end jewelry. We sell thousands of carats of gemstones per month. So when we set aside a gemstone as being top jewelry grade, that means that that gemstone has been chosen from hundreds of others as the very best 5% of the stones we bring in.