Moissanite Double Refraction Explained

Published on: October 13, 2022
Last Updated: October 13, 2022

Moissanite Double Refraction Explained

Published on: October 13, 2022
Last Updated: October 13, 2022

Moissanite double refraction is a well-known property of this diamond alternative which gives the inside a blurry effect.

A light ray is slowed down, bent, and split in half as it passes the gemstone.

Moissanite is double-refractive and is not a problem if the stone is cut correctly. Double refraction is invisible to the naked eye.

When a light ray passes through it, the light is dispersed in ‘two.’ 

Moissanite has the world’s highest refractive index of 2.65.

It has the most remarkable ability to bend light to its deepest parts.

Some customers are unaware that moissanite is double reflective.

This article will show you everything you need to know about this property and how to observe it.

What Is Moissanite Double Refraction

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Double refraction refers to the process in which one unpolarized light beam is split into two light rays.

These rays are then polarized in planes that are mutually perpendicular to one another. It’s also referred to as birefringence. 

When an unpolarized light ray strikes a crystal such as Peridot, tourmaline, zircon, and sapphire, it produces two refracted rays.

The first is an ordinary ray, which follows the refraction laws, and the second is an extraordinary ray, which does not.

Unlike many other diamond simulants, moissanite exhibits an optical illusion.

This effect is termed double refraction, and it happens when a light ray is slowed, bent, and split into two upon entering the gemstone. 

However, it is frequently cited as a disadvantage by moissanite critics claiming the double refraction will cause the stone to appear blurry.

When it is cut so that the single refraction direction is through the table, the doubling effect is not visible from the top.  

Moissanite has an optic axis, at least one direction in which the substance behaves as a singly reflective gem.

When a light ray passes through the gemstone at this axis, it does not break and split into two light rays. 

It is cut with the optical axis perpendicular to the table, so the doubling effect is not seen from above.

Your moissanite should be adequately cut as long as it comes from a reputable source.

How To Detect The Double Refraction Effect

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It is essential to know that the doubling effect is not visible parallel to the optical axis.

The best way to see this effect is to view the gemstone from above at an angle with a 10x jewelry magnifying lens. 

You will notice two slightly blurry joints caused by the moissanite double refraction.

When looked at in the position used to check for polish lines, the lines connecting the bezel facet to the top appear doubled.


While many still think of moissanite as a fake diamond, it’s quickly becoming one of the most popular diamond alternatives, particularly for engagement rings.

The doubling effect is a property that contributes to the gemstone’s amazing fire to some extent. 

This effect offers comparable sparkles at a much lower price.

Therefore, while moissanite double refraction is a noticeable feature, it has no adverse effect on its beauty and durability. 

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Written by Kelly Indah

I’m a statistics researcher here at EarthWeb with a special interest in privacy, tech, diversity, equality and human rights. I have a master’s degree in Computer Science and I have my Certified Information Systems Security Professional (CISSP) certification.