Understanding Gemstone Brilliance and Fire
Moissanite out-sparkles other gems.
What is gemstone brilliance?
Your gemstone’s sparkle, or brilliance, is an optical property affected by its brilliance refractive index or BRI. When talking about brilliance in gemstones, we are referring to the light refracting in the interior of the stone, not the light reflecting off its surface. Brilliance is one of three terms used to describe the appearance of a gemstone as it reflects light. The other two are fire and luster. Let’s focus here on the first two, as luster describes the non-metallic or metallic appearance of the gem’s surface when it reflects light.
What is gemstone fire?
When light hits your gemstone and reflects, you see a sparkle and a prism of colors. These colors are known as fire. The gemological term for this is dispersion. When pure white light enters a non-opaque object such as a gemstone, it breaks into different wavelengths of light that are refracted by its internal facets. These spectral colors are the rainbow-like effect you see when you look at a gemstone.
What makes moissanite more brilliant than other gems?
A stones refractive index is determined by directing light into the gemstone and then measuring the speed light reflects or refracts off its facets. The numerical result is calculated by comparing the speed of light in air vs. the speed of light in the gemstone.
All minerals are measured on a scale and range from 1.2 to approximately 3. With a BRI of 2.65 to 2.69, moissanite is the world’s most brilliant gemstone. This means the speed of light refracting in moissanite is 2.65 to 2.69 times slower than the speed of light in the air. Similarly, the refractive index of a diamond is 2.42, meaning the speed of light in the diamond is 2.42 times slower than the speed of light in air.
| Gemstone | Refraction Index |
| Moissanite | 2.65 – 2.69 |
| Diamond | 2.41 – 2.42 |
| Ruby | 1.76 – 1.77 |
| Sapphire | 1.76 – 1.77 |
| Emerald | 1.56 – 1.60 |
When looking at your gemstone, its brilliance is simply the amount of light reflecting out of the crown of the stone to your eye. Each gemstone’s angle of refraction is unique, meaning every stone will refract light differently. This helps jewelers distinguish between gemstones such as rubies and garnets.
How does moissanite’s fire rating compare to other diamonds and gems?
Moissanite’s fire exceeds that of diamond, ruby, sapphire and emerald, as well as other popular gemstones. As a scientific measurement, moissanite’s dispersion is 0.104, which means it has 2.4 times the fire of a diamond.
The further the opacity of a gemstone drops, or the more color that is added, the smaller its dispersion measurement. This is reflected in the dispersion of darker-colored gems:
- Moissanite – 0.104
- Diamond – 0.044
- Ruby – 0.018
- Sapphire – 0.018
- Emerald – 0.014
Moissanite possesses 5.7 times and 7.4 times more fire than ruby, sapphire and emeralds, respectively. There is no other gemstone, natural or man-made, that compares to the brilliance of moissanite.
Does moissanite retain its brilliance and fire?
Yes. Your moissanite’s brilliance and fire will be the same on day 3,570 as it was on day one. Additionally, Charles & Colvard provides a warranty on every gemstone, guaranteeing that every Charles & Colvard created moissanite gemstone will maintain its brilliance and fire for the lifetime of the stone.
The brilliance of moissanite is unrivaled among popular gemstones today. For more information about moissanite’s qualities, refer to our Moissanite FAQ Section.
