Diamonds are one of the most beautiful, and most expensive, jewels available today. They are also extremely popular. Diamonds are an important symbol of engagement in many parts of the world, and they also appear in everything from simple earrings to the tiaras and crowns worn by royalty!

Because they are so popular and expensive, diamonds have been a favorite area for imitation over the years. Cut glass, rhinestones, and cubic zirconium are all attempts to replicate the beauty of diamonds at a lower cost. None of these are particularly good imitations -- they lack the luster and brilliance of the real thing.

Technology's latest attempt to replicate the diamond is a product called Moissanite. In this edition of How Stuff Works, you will learn about this interesting jewel. We will discuss its history, qualities, creation, and availability!

Moissanite History
In 1893, Nobel Prize-winning French scientist Dr. Henri Moissan discovered minute quantities of a new mineral, natural silicon carbide. The mineral was located in an ancient meteorite found in the Diablo Canyon in Arizona. Later named "moissanite" in honor of Dr. Moissan, this mineral's supply was too limited for jewelry use.

More than a century later, Cree developed a process for producing large, single crystals of moissanite. In 1995, a master diamond cutter observed samples of the silicon carbide crystals and suggested to the founders of Charles & Colvard that, if properly cut, the crystals could make a beautiful jewel. Charles & Colvard recognized the mineral's potential. They also realized that in order for the moissanite jewels to be used, they would have to be manufactured -- there is essentially no natural supply for this stone. In 1995, Charles & Colvard partnered with Cree (a NC-based R&D lab) to develop larger gemstones for Charles & Colvard to use in the Cree colorless development program. In conjunction with Cree, Charles & Colvard is the exclusive worldwide manufacturer and marketer of lab-created moissanite gemstones.

Moissanite Qualities
Moissanite gemstones rival diamond, ruby, emerald, and other fine gemstones in their brilliance, fire, luster, and incredible hardness, as illustrated in the following Comparison Chart:

Refractive Index
(Brilliance)
Dispersion
(Fire)
Luster Index
Mohs Hardness
Toughness
Specific Gravity
Moissanite
2.65-2.69
0.104
20.4%
9.25
Excellent
3.21
Diamond
2.42
0.044
17.2%
10
Good*
3.52
Ruby
1.77
0.018
7.4%
9
Excellent**
4.00
Sapphire
1.77
0.018
7.4%
9
Excellent**
4.00
Emerald
1.58
0.014
4.8%
7.5
Good-Poor**
2.72
* In cleavage direction, otherwise excellent
** Except twinned stones

Source: Charles & Colvard

The Mohs Scale
Source: Kingzett's Chemical Encyclopedia
The Mohs Scale is used to determine the hardness of solids, especially minerals. It is named after the German mineralogist Friedrich Mohs. As indicated in the chart above, moissanite has a Mohs Hardness rating of 9.25. The scale reads as follows, with the hardness and mineral given from softest to hardest:

  • 1 - Talc: easily scratched by the fingernail
  • 2 - Gypsum: just scratched by the fingernail
  • 3 - Calcite: scratches and is scratched by a copper coin
  • 4 - Fluorite: not scratched by a copper coin and does not scratch glass
  • 5 - Apatite: just scratches glass and is easily scratched by a knife
  • 6 - Orthoclase: easily scratches glass and is just scratched by a file
  • 7 - Quartz (Amethyst, Citrine, Tiger's Eye and Aventurine): not scratched by a file
  • 8 - Topaz
  • 9 - Corundum (Sapphires & Rubies)
  • 10 - Diamond: cuts glass


Step 1: The Preform


Step 2: Preform & Dop


Step 3: Pavilion, Post-grinding


Step 4: Cut & Polished Girdle


Step 5: Cut Facets


Step 6: Polished Facets


Step 7: The Stone's Crown


Step 8: Polished Table


Step 9: Finished Gemstone

Chemical Hardness
Perhaps you've wondered "Why is a diamond so hard?" Diamonds are a naturally occurring mineral, one of two crystalline forms of the element Carbon. Chemically, diamonds are pure carbon crystals, and each carbon atom is held tightly by four bonds to other carbon atoms nearby. Diamonds are the hardest naturally occurring substance known because of the strength of these bonds. You may have heard about the strength of carbon fibers -- carbon fibers have incredible strength for the same reason.

Why is silicon carbine (SiC) nearly as hard? Silicon carbine relies on carbon bonds as well for its strength. Silicon carbide is the third hardest compound known to mankind. In addition, the physical and electronic properties of SiC make it the foremost semiconductor material for short wavelength optoelectronic, high temperature, radiation resistant, and high-power/high-frequency electronic devices (hence Cree's initial interest in it). Moissanite is created with silicon and carbon, through a combination of pressure and heat.

How a Moissanite Stone is Created
To begin the moissanite production process, Charles & Colvard receives single silicon carbide crystals from Cree. The crystals are precision cut into small pieces called preforms, as shown in Step 1.

The preforms are then sent overseas to high-volume faceting vendors who hand-cut and polish the preforms to Charles & Colvard standards, which are designed to maximize the gemstone's brilliance and fire. As Step 2 shows, the vendor then attaches the preform to a guidance tool, or dop to aid in the grinding process. Moissanite jewels are shaped with a tool called a faceting machine. To understand this tool, imagine a record player. The faceting machine acts as the record table, spinning around. It is made of either steel or aluminum, and has industrial-grade diamond chips embedded in it (that's what cuts and polishes). The dop acts as the record player needle, gently guiding the moissanite preform down to the spinning faceting machine. It's the friction between the gemstone and faceting machine that shapes the stone. The faceting vendor uses the faceting machine to cut and polish each moissanite preform. Using the dop, the gemstone is rotated for an even shape and polish.

The lower portion of the gemstone, or pavilion is formed by grinding the pavilion (Step 3). Then the girdle (the edge of the stone that is grasped by the setting) is cut and polished (Step 4), and then the pavilion facets are cut (Step 5) and polished (Step 6).

Next, the gemstone is removed from the dop and reattached with the top of the stone, or crown, exposed for cutting (Step 7). The crown facets are cut and polished. Finally, the table (the upper flat surface) is polished (Step 8). The resulting gemstone (Step 9) is returned to Charles & Colvard for inspection, sorting, grading, and shipping to select jewelry stores.


Comparison Shopping
If you know much about diamonds, you know that diamonds are graded according to what is commonly known as the "Four Cs." The Four Cs consist of:

  • Cut, which affects a diamond's brilliance, as brilliance relies on light optics and the ideal angles to produce the maximum effect. A deeply cut stone will affect the way light reflects in the mass of the diamond. A very shallow cut stone will seem dark because the light exits the back of the stone and the angles do not reflect the light back up through the top of the stone to your eye.
  • Clarity, which is determined by the amount and severity of inclusions and flaws visible under 10-power magnification
  • Color, the less color a diamond shows (i.e., the whiter it appears), the better diamond it is. The exception includes extremely valuable "fancy colored diamonds" and less expensive enhanced "irradiated" stones
  • Carat, which is the traditional measuring unit of a diamond's weight (1 carat = 200 milligrams). A carat is divided into 100 "points," so the same diamond can be represented as weighing a carat and a half, 150 points or 1.50 carats.
Moissanite jewels are inspected by trained graders and are scored on a scale specific to moissanite. All of the jewels sold are of "very good" quality, so unlike some other jewels, you will not find moissanite that is off-color or visibly imperfect. All of the jewels sold are of good color and are "eye clean," meaning you cannot see imperfections with the naked eye. Because its physical properties are different than a diamond, moissanite is not graded in the same manner. Cut and carat weight are fairly similar, but moissanite weighs differently than diamond, so it is not an "apples-to-apples" comparison. The retail cost of moissanite is based upon the cost of the gold and the setting in addition to the cost of the jewel. As a general rule, with all other things being equal, a moissanite retails for about 1/10th the cost of a diamond.

Moissanite gemstones are such a close match to diamonds that even skilled jewelers cannot tell the two apart. Like diamonds, moissanite gemstones have inclusions and color differences. Charles & Colvard's patented Tester Model 590 (photo below) is the only recommended instrument that has been developed to distinguish moissanite from diamonds. The tool reliably and easily distinguishes colorless moissanite gemstones.


The patented Tester Model 590
Source: Charles & Colvard Annual Report

Where to Find Moissanite Jewelry
Only in the last few years has the word about moissanite spread. In 1999, Charles & Colvard launched its first national advertising campaign, including television ads, and print/display ads in Harper's Bazaar, airports, and shopping malls in select markets. Targeted image ads have run in publications including People magazine and Southern Living. The stone has also been shown at regional, national, and international jewelry trade shows. Moissanite is available only at select jewelers and in fine jewelry settings. Authorized jewelers can offer customers the opportunity to create unique, custom moissanite jewelry accompanied by Charles & Colvard's Certificate of Authenticity and Limited Lifetime Warranty. To find an authorized retailer near you, visit the Moissanite Web site or call 1-800-210-4367.

Links

Special thanks to Jessica Blue at Richard French & Associates (PR firm for Charles & Colvard) for her contributions to article.