7 Jewelry Terms You Need to Know


Windowing is an optical phenomenon that occurs when light passes through a gemstone without being refracted. If windowing is present in a gemstone the observer can look through the stone at certain angles as if it were a window or can observe large dark areas in the stone (caused by light leaking out the window).

A well-cut stone should reflect so much light that nothing is seen behind it. However, this statement presumes that you are looking straight down through the top of the stone, and the stone is not tilted at all. Tilting the stone even slightly will change the angles of light hitting the pavilion facets. Each type of gem has its own range of "tilt brilliance". The lower the refractive index the less tilting it takes to window the stone.


Durability is a material's ability to remain intact or withstand exposure to temperature and chemicals. Moissanite can easily withstand temperature variations during the jewelry manufacturing process and repairs at a jeweler's bench (unlike other gemstones such as cubic zirconia or emerald). In fact, Moissanite has a higher vaporization temperature than diamond and can withstand temperatures reaching 2,000 degrees Fahrenheit.

Moissanite is also very stable when exposed to various chemicals, solutions and acids typically used during both manufacturing and jewelry repair that commonly damage other less stable gemstones.


Hardness refers to a gemstone's resistance to being scratched or abraded and is commonly expressed as a number ranking (1 being the softest and 10 being the hardest) on the Mohs relative hardness scale.

Moissanite ranks 9.25 on the Mohs scale making Moissanite one of the hardest gemstones on earth. It's unusually high hardness makes scratching and abrasions very rare, even after many years of daily wear and tear.

Moissanite's ability to resist abrasion and scratching easily outranks and is more than double (120%) the hardness of any popular diamond simulants such as Diamond Nexus (CZ), Russian Brilliants (CZ), or Sona Diamond (CZ).


The ability of a gemstone to remain intact, withstand force (pressure) and resist breaking or chipping is known as toughness. Determined by a substance's atomic and chemical structure, toughness can vary directly within a gemstone.

While both Moissanite and diamond are rated excellent in toughness, Moissanite has a different atomic structure than diamond which does not have a direction of cleavage (which sometimes is considered as a direction of structural weakness) like diamond. Simply said, Moissanite outranks diamond in overall toughness.


Luster is the amount of light that is reflected back to the observer from the surface of the gemstone. In addition to superior fire and brilliance, Moissanite has 18% greater luster than a diamond and 50% greater luster than CZ.

Brilliance & Refractive Index

The refractive index is the measurement of a gemstones ability to slow down, bend, and reflect light. The greater the R.I., the greater the brilliance of the gemstone.

Brilliance is the flashes of white light exiting the top and sides of a gemstone.

Moissanite's superior refractive index makes Moissanite the most brilliant fine gemstone on earth.

Fire (Dispersion)

Fire (also called dispersion) is when light enters a gemstone (Moissanite, diamond, CZ, etc.) and is split into all the different colors of the rainbow. Fire is colored light flashes.

Moissanite has 250% the fire of diamond