Diamonds are the world’s most popular gemstones. Many times more money is spent on diamonds than on all other gemstones combined. Part of the reason for diamond’s popularity is a result of its optical properties – or how it reacts with light. Other factors include its durability, fashion, custom, and aggressive marketing by diamond producers. Diamond serves as the birthstone for the month of April.

Diamonds have a very bright luster – the highest non-metallic luster – known as “adamantine.” Their high luster gives them the ability to reflect a high percentage of the light that strikes their surface. This is one property that gives diamond gemstones their “sparkle.” And, when a diamond is being fashioned into a gem, the facet angles are planned to reflect a maximum amount of light from its internal surfaces.

Diamond also has a high dispersion. As white light passes through a diamond, this high dispersion causes that light to separate into its component colors. Dispersion is what enables a prism to separate white light into the colors of the spectrum. This property of dispersion is what gives diamonds their colorful “fire.”