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Instead of Other Gems Proper Care of Moissanite Jewelry Discover Superior Fire of Moissanite

Discover Superior Fire of Moissanite



CUT: Its Relevance and Importance As It Pertains To A Jewel's Optical Physics

FINE JEWELRY APPLICATION

EARL R. HINES
VICE PRESIDENT OF MANUFACTURING
CHARLES & COLVARD LTD

KURT NASSAU, PH.D., FGA (HON)
NASSAU CONSULTANTS


"Moissanite jewels have more brilliance, fire and luster than any other hard jewel. These essential properties - brilliance, fire and luster - are what determines a Jewel’s beauty.

This booklet has been developed to provide you with the scientific background to support Charles & Colvard's marketing claims that Moissanite actually has more of these highly valued and prized attributes than any other jewel used today for the creation of fine jewelry - including diamond."



The crown and paviliion of a jewel.

fundamentals of jewel proportion

The crown of a jewel acts as a window, allowing light into the jewel, and light that has entered the jewel to then exit, The pavilion of a jewel acts as a mirror to reflect light back out of the crown. Light that leaves through the pavilion is potential brilliance lost and is defined as leak­-age. Light leaving the crown travels upward and is seen by the eye as brilliance.

Optical Physics: The Science Of Brilliance

Brilliance is determined by the amount of light that a jewel reflects back to the eye. When light strikes a material other than a vacuum, it meets resistance and slows down. In the case of jewels, the slower the light travels, the higher the resulting potential brilliance.
Speed of light Comparison for Selected Near-Colorless Materials
  Vacuum 186,282 mps*
  Sapphire Cubic 105,244 mps
  Zirconia 85,844 mps
  Diamond 76,976 mps
  Moissanite 70,295 mps
  * miles per second  
Note: There are slight variations in the published numbers of different journals. All numbers used here and throughout this publication, are nominal and widely accepted

Maximizing Brilliance in Jewels


Incident, reflected and refracted rays.
Brilliance is light leaving the crown of a jewel traveling upward which is visible to the eye, and is created in two different ways:

1. LUSTER - Reflection from the Surface

When available light (incident rays) meets a surface, some of it reflects and some enters the material. The reflected light is referred to as "first surface reflection" or LUSTER and depends upon the Refractive Index (R.I) of the material. See illustration to the right.

       

Reference: GEMS by R WEBSTER Fifth Edition, pg. 729, Fresnel's Formula.

"Since this (luster) is determined by the refractive index (along with the flatness of the polished surface), the higher the luster, the higher the refractive index."
Reference: Handbook of Gem Identification published by Gemological Institute of America, pg. 216.
The luster is measurable with an instrument. Luster meter by Hanneman or Jemeter. (The surface must be perfectly clean.)
Reference: GEMS by R. WEBSTER Fifth Edition, pp. 730-734.


Exploiting Inherent Fire

Dispersion (Fire)DISPERSION (FIRE)

In physics, "dispersion" (fire) is the property by which light is spread out according to its wavelengths (colors) as it passes through an object. For example, when white light is directed into a prism, the different colors of light bend in different degrees so they spread out to make a rainbow, as pictured below. This occurs because different colors of light have different refractive indices in a given material. Each color interacts with the molecular structure of the prism differently, depending on its wavelength and the material. Different wavelengths of light bend in different degrees by the dispersion. This is also known as "dispersive refraction". A geographical representation of dispersion (fire) for moissanite and diamond is shown below.
           
SYNOPSIS: DISPERSION (FIRE)
  • Highly refractive, near-colorless jewels rely on fire and brilliance for beauty.
  • Diamond?s ideal cut has proportions that maximize the FIRE ? therefore reducing the potential brilliance. This is desirable because of diamond's relatively low dispersion and provides the balance that results in the most beauty in diamond.
  • Moissanite that is well cut has proportions that maximize BRILLIANCE - therefore reducing potential fire. However, moissanite's greater dispersion allows it to maintain dramatic fire effects that are greater than can be achieved in other materials, including diamond.

Moissanite has dispersion of 0.104,
which is greater than both cubic zirconia (0.060) and diamond (0.044).
Note:
The diameter of a jewel's dispersed light is determined by a combination of its dispersion and refractive index.
The J-Fire Unit developed by
Charles & Colvard is used to
illustrate a jewel's dispersion
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