"Hearts and Arrows" designs are a gold standard for many diamond buyers, but are very uncommon in the colored stone world. What's the attraction? It's not so much the pattern that can be seen with special viewers or photographs, but rather that it's an easy way to quickly identify which gemstones have excellent proportions, symmetry, cutting, clarity, and polish. All of these need to be absolutely perfect in order to generate this pattern, which results in a brilliant and dazzling gemstone. If you see this or a similar pattern in a gemstone it's proof that it's been cut "just right".