Questions & Answers

Joy of London Jewels provides Jewelry and Accessories in a warm and friendly shopping environment.

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Moissanite Information


Moissanite is a unique near-colorless jewel made from silicon carbide (SiC) that outshines all others with its unsurpassed fire and brilliance. Moissanite, also known as silicon carbide (SiC), is a naturally occurring mineral found in limited quantities or as small particles in the earth.

For years, scientists tried to re-create this extraordinarily brilliant material. Only recently through the power of advanced technology moissanite been developed a way to duplicate this unique and near-colorless jewel by producing large, gem-quality crystals. Moissanite is truly a unique and beautiful blend of art and science.


Discovered in 1893 by French Nobel Prize-winner, Dr. Henri Moissan, the jewel was later named in his honor.


Single-crystal moissanite is manufactured through a patented thermal growing process, the specifics of which are proprietary. The process is very difficult and expensive, thus preventing mass production.


Moissanite gemstones are produced within exacting specifications and high quality control standards. The Certificate of Authenticity ensures that every gemstone is an original product which has been manufactured in controlled facilities by highly skilled specialists using the latest technology. Moissanite created gemstones are released for sale only after having met stringent quality control standards.

What makes moissanite “sparkle”? What characteristics of moissanite give it such exceptional brilliance?

The Refractive Index (RI) of a gemstone is the most important optical property affecting its potential brilliance (sparkle). With an RI of 2.65 – 2.69, moissanite displays more brilliance than diamond (RI 2.42) or any other popular gemstone, such as ruby (RI 1.77) and sapphire (RI 1.77). (See Chart below):


Refractive Index Dispersion Luster Hardness (Mohs Scale) Toughness












Excellent *






Excellent **






Excellent **






Good to Poor

* In cleavage direction, toughness is "good"

** Except twinned stones

Will moissanite’s brilliance ever fade?

Moissanite comes with a Limited Lifetime Warranty which guarantees that every Moissanite gemstone will maintain its brilliance and fire for its lifetime.


Does moissanite have any identifying characteristics such as inclusions?

Though moissanite is not sold with eye-visible inclusions, needle-like inclusions are inherent to the crystal growth process and can be seen under magnification.

How is moissanite graded for clarity?

Using a 10x loupe, each individual jewel is examined for inclusions that may affect moissanite’s optical performance.


Is moissanite available in different colors?

Most moissanite sold today is near-colorless.

Is moissanite graded on the GIA diamond color grading scale?

The Moissanite NEO does grade on the GIA color grading scale.

Can the color of moissanite change?

No. There are no likely situations in which the color of moissanite will be permanently changed. A temporary color change will occur when moissanite is exposed to heat (torch) during jewelry repair techniques. However, with proper bench techniques, there is no resulting damage and moissanite returns to its normal color after the jewel cools to room temperature.

Are moissanite jewels hand-cut or mass produced?

Moissanite gemstones are precisely hand-cut by a master gem cutter to create maximum brilliance which intensifies its ultimate fire.

What shapes are available?

While round brilliant continues to be the most popular cut for moissanite, fancy cuts such as castle, cushion, heart, marquise, octagon, oval, pear, princess, radiant, square brilliant, triangle and trillion are also available in limited quantities.

Fire (Dispersion)

What gives moissanite its fire?

A gemstone’s “fire” is caused by dispersion – the property by which light is spread out according to its wavelengths (colors) as it passes through an object. Moissanite’s dispersion is 0.104 and can be calculated scientifically.

How does moissanite’s fire compare with that of other popular gemstones?

Moissanite displays 2.4 times more dispersion or fire than diamond (0.044) and much more dispersion than ruby (0.018), sapphire (0.018) and emerald (0.014).

Will a moissanite jewel ever lose its fire?

Moissanite comes with a Limited Lifetime Warranty which guarantees that every Moissanite will maintain its fire and brilliance for its lifetime.

Hardness (Resistance to Scratching)

Is moissanite resistant to scratching?

Yes. Moissanite is durable and tough. It is extremely resistant to scratching and abrasion. Diamond is the hardest gemstone used in jewelry but moissanite, with a hardness of 9.25, is harder than all other gemstones including ruby and sapphire.

Toughness (Resistance to Breaking)

Can moissanite break easily?

No. Based on measurable scientific studies in high pressure research, moissanite is extremely resistant to breaking and chipping. In fact, moissanite is one of the toughest jewels known to man and can stand the test of time.

Is moissanite heat tolerant?

Yes. Moissanite has heat resistance properties superior to many other jewels. Tests prove that at 2000¢ªF, higher than the equivalent intensity of a house fire, moissanite remains intact and as brilliant as the day it was created. High heat tolerance makes moissanite less likely to experience heat damage during jewelry repair.

Identifying Moissanite

How can moissanite be distinguished from other colorless jewels?

There are) methods for distinguishing moissanite:

  • Determine if doubling of facet junctions is visible through magnification.
  • Unique needle-like or micropipe type inclusions that typical are perpendicular to the table facet are visible only under magnification in a percentage of moissanite.
  • Specific gravity and refractive index are important attributes in gemstone identification useful for a gemologist with appropriate equipment to identify moissanite.

Is it true that created moissanite can test positive as diamond using conventional testing equipment?

Yes. Near-colorless created moissanite has many similar physical properties to those of diamond and will test positive for diamond when using a thermal diamond tester.

Sales & Customer Service

Why is moissanite sold by millimeter and not by carat weight?

Moissanite is listed in millimeters because it is easier for a jeweler to order moissanite in millimeters to be able to determine the size needed for mounting. Also used is diamond equivalent weight (dew). This is the method by which most retailers are used to selling and consumers are used to buying.

Carat is the traditional measuring unit of a diamond's weight. Moissanite stones are slightly lighter than diamonds. For example, a 6.5mm round diamond would weigh 1.0 ct, while a 6.5mm round moissanite would weigh 0.88 ct. The two stones would be the same size - 6.5mm in diameter. All stones on are listed with their actual size in mm and/or the diamond equivalent in carats.

Does moissanite retain its value over time?

Because of its rarity, unmatched beauty, and patent protection, Moissanite is expected to retain or increase in value over time.

Jewelry Repair & Care

How do you clean moissanite?

You can clean moissanite the same way you would diamond or any other fine gemstone. As with any fine jewelry item, you would not want to dump all of your jewelry into an ultrasonic cleaner at once to guard against possible chipping, but your moissanite jewel is perfectly safe under normal ultrasonic cleaning. You can also clean moissanite with a commercial (non-acid based) jewelry cleaner or mild soap and water using a soft toothbrush.

How does moissanite hold up in repairs and sizing?

Moissanite is a highly stable material. It is durable and tough, extremely resistant to scratching, abrasion, breaking, or chipping. In addition, high heat tolerance makes moissanite less likely to experience heat damage during jewelry repair.


    What is Heat Treatment as it applies to colored gemstones?

      Heat Treatment

      Centuries ago, someone stumbled upon the magical effect of applying heat to gemstones. High heat, such as that from a charcoal fire, can make a bland looking gemstone change its color into something spectacular. If this fortunate technique was not discovered, there would be very few affordable gemstones of good color on the market.

      Heat treatment is considered to be a natural type of enhancement as it is a continuation of the processes that occur in the earth when the stone was originally formed. During treatment, the stone is heated to very high temperatures (approximately 1600 Celsius) causing inclusions, chemical elements, and other impurities to reform themselves and change the color of the stone. This color change may result in the stone being darker, lighter, more intense or of a different color. An example of this is the dissolving of rutile silk inclusions in blue sapphires, which improves both clarity and color. This heat treatment is permanent and irreversible.

      Another example is ruby. This is a stone that is commonly heat treated. Only the most valuable and expensive rubies possessing the richest colors are not heat-treated. Ruby is heated almost to its melting point, allowing the aluminum oxide in the stone to reform, creating a new crystal structure. This allows the chromium in the stone to combine with different atoms, allowing for a better red hue. The same can apply to a type of sapphire known as gouda sapphire. These milky white sapphires turn blue, and account for many of the quality sapphires on today's market.

      Detection of heat and diffusion treatment is possible because these treatments modify natural inclusions. The destruction of gas or fluid inclusions or the dissolving of mineral inclusions are clues to heat treatment. For gems that contain rutile needles, the needle margins may become diffuse. On rubies, inclusions may be found that are glassy in appearance. These are caused by borax-based substances that are used in the heat treatment process.

      It is usually more difficult to find out if a stone has not been treated than if it has. Unadulterated stones can be harder to verify. However, there are some clues that can help. For example, gemologists can examine the inner workings of the stone and study the inclusions for signs of heat treatment. For example, if the stone has been treated, tiny inclusions such as small crystals will melt during the heat treatment process. A gemologist can easily see this using a microscope. An absence of such evidence could suggest an untreated stone.

      Centuries ago, men sitting in front of charcoal fires were the first practitioners of the art of heat treatment. They would use pieces of bamboo to blow air into glowing charcoal where a few stones were placed, in an attempt to coax some new colors into their stones. Today, the technology is much more sophisticated, with professionals using large computer controlled electric furnaces. The old, crude methods are gone, but the result is still the same; drab gemstone are turned into something beautiful. This allows us all to have the chance to own a colored gemstone that we can be proud to show.

      Amethyst, citrine, ametrine, aquamarine, tourmaline, topaz, light green tourmaline, sapphire, ruby, tanzanite, and blue zircon are gemstones that are typically color-enhanced by heat treatment. Here is a full list of the more commonly heated stones and how heat treatment enhances them.

      Amethyst - lightens the color and will change the color of pale amethyst to "yellow" that will be sold as citrine.

      Aquamarine- removes the greenish undertones that are common in this stone to produce a more blue stone. Also deepens the color.

      Citrine- often produced by heating varieties of quartz.

      Kunzite - to improve color.

      Morganite - heat treatment changes the color from orange to pinkish.

      Ruby - heat treatment improves color, removes iron stains, dissolves inclusions and fills tiny cracks.

      Sapphire - to lighten or intensify color and to improve the uniformity of the color.

      Tanzanite - to produce a more desirable blue shade.

      Topaz - when used with irradiation, heat treatment will produce shades of blue. Also done to produce a pink topaz.

      Tourmaline - to lighten darker shades of tourmaline. This is usually done with the green and blue varieties.

      Zircon - to produce red, blue, or colorless stones.