Hearts On Fire master diamond cutters apprentice for between 5 and 10 years before they can cut a 1+ carat diamond, and when they do, our process is so rigorous and exacting that it takes 4 times as long to cut a Hearts On Fire diamond than it would take to cut a generic diamond. The first measure of a diamond’s sparkle is brilliance, or how well it reflects white light. When you see a diamond sparkling in a dimly lit or candlelit room, what you’re seeing is its brilliance. If a diamond isn’t cut correctly, it will appear dim and dull, even in perfect lighting.