Cubic zirconia (CZ) is the cubic crystalline form of zirconium dioxide (ZrO2). The synthesized material is hard, optically flawless and usually colorless, but may be made in a variety of different colors. It should not be confused with zircon, which is a zirconium silicate (ZrSiO4.) Introduced to the jewelry market almost 50 years ago, they've remained highly sought substitutes for real diamonds due to their affordability, non-resource depleting supply and excellent value. Cubic Zirconia jewelry offers glamorous appeal at a fraction of authentic diamond prices. As with precious stones, "clear" remains the most popular color, however, CZ stones are now available in many attractive colors that gain in popularity each year.
Cubic zirconia (also known as CZ) is similar to a diamond with its brilliance and crystal clarity, but it is a synthesized (man-made) crystalline material that is colorless, hard, and flawless. It looks so much like a diamond, it is an affordable alternative to diamonds. It can made in different colors to simulate the different colors of a diamond.
Cubic zirconia started being produced in 1976 because of its diamond-like qualities, low cost, and overall durability. Cubic zirconia is a mineral that is used as a diamond simulant and is widely synthesized.
Sometimes, people mistakenly call it cubic zirconium. Zirconium is a different chemical element that is a metal that is silvery white. This element in its powdered form is used with other elements to create a cubic zirconia.
Cubic zirconia crystals are made by melting powdered zirconium and zirconium dioxide together and heating them up to 4,982ºF. A cubic zirconia is a perfectly man-made, flawless stone that is free of inclusions or imperfections.
There are ways to distinguish cubic zirconia from a diamond, as follows:
- Thermal conductivity: Diamonds are thermal conductors while cubic zirconia is a thermal insulator. This is what makes the diamond stand out next to the cubic zirconia with special instruments.
- Hardness: Diamond has a rating of 10 and Cubic zirconia has an 8.5 on the Mohs hardness scale.
- Density: Cubic zirconia is 1.7 times denser than a diamond.
- Refractive index: Diamond has a refractive index of 2.42 vs. Cubic Zirconia has an index of 2.15-2.18
- Cut: Diamonds are typically cut differently than cubic zirconia gemstones.
- Dispersion: Diamond 0.044 vs. cubic zirconia 0.058-0.066
- Color: Cubic zirconia is equivalent to the perfect “D” on diamond’s grading scale but it also comes in other colors as well, such as green, orange and pink, etc. Most diamonds on the other hand have a brown or yellow tinge to them, and only the rarest are truly colorless with diamonds.
- Inclusions and imperfections are non-existent in cubic zirconia. Since they are machine cut to very high precision, maximum light transmission is assured. (See image figure below.)
The Power of Light
The cut grade of stones is determined by how successfully it interacts with light. Three of the visual effects that are created are:
Brightness: Internal and external white light reflected from the stone
Fire: The scattering of white light into all the colors of the rainbow
Scintillation: The amount of sparkle a stone produces, and the pattern of light and dark areas caused by reflections within it.
Here are images of what happens to light (blue line) when it hits a gemstone with three different qualities of cut:
Can you tell a cubic zirconia stone from a real diamond with the naked eye?
Professionals can, of course, as could anyone with high-powered magnification equipment. For the average person, the differences are very slight. At average viewing distance, most won't notice the difference between a well-manufactured CZ and an authentic diamond. Most importantly, there is no longer a stigma regarding "fake" jewels. People want the look they covet at the price they can afford and everyone else is fine with that. Affordable jewelry and bling have become ubiquitous in modern society as women use imitation jewelry for all occasions. No longer is the satisfaction of wearing fine accessories reserved for the wealthy.
Of all faux materials, Cubic Zirconia best matches the characteristics of natural diamonds. Among the subtle difference are hardness, brilliance and fire. At 8.5 on the Mohs scale, Cubic Zirconias are slightly softer than natural diamonds (10) and harder than glass (6.5) They have less brilliance (sparkle) due to the diamond's hardness and ability to sustain more intricate cuts. CZ stones contain more fire (rainbows) than natural diamonds. Cubic zirconias are machine cut to the same exacting tolerances as natural diamonds. Like a diamond, CZs can be cut in a variety of shapes and sizes.
Most popular cut shapes:
The round cut is considered the most classic and popular of all gemstone cuts. The round brilliant cut offers a balanced return of light (brilliance) and dispersion with a stunning 58 facet cut. It is designed to give maximum brilliance and radiance.
This elongated shape offers a perfectly symmetrical design. The shape gives a flattering illusion, adding length to the hand-great for shorter fingers or petite hands. The oval shaped gemstone is a variation of the round brilliant cut, which has been squeezed so that it is narrower on one direction and longer in the other.
The Princess Cut
Fit for a princess! This increasingly popular cut is a square cut with 90 degree angles on each corner, capturing radiant brilliance. It is a great improvement over the previous step cut used for square and oblong gemstones. It is effectively a square version of the round brilliant cut, and is known technically as a square modified brilliant cut. Because of the extra faceting and the effects it produces, princess cuts are naturally more brilliant and sparkly than ordinary square gemstones.
The Emerald Shape
The emerald cut is also known as the “step cut”. Step cuts are comprised of larger facets which act like mirrors. Its concentric, broad, flat planes resemble stair steps. It is rectangular in shape and has cut corners. The emerald cut gemstone reveals a truly classic beauty and simple elegance.
The Pear Shape
The pear shape, also called the teardrop shape, is a variation is a hybrid cut combining the best qualities of oval and marquise cuts. Many who like the look of the Round but want the fancy shape alternative, choose the pear shape. This particular cut is perfect for pendants and earrings, creating a spectacular sparkle and brilliance.
The Heart Shape
The heart shape is surely the romantic shape for a gemstone. Basically, it is a pear shape with a notch cut into the rounded end. Truly unique and special, the heart cut is the ultimate symbol of love.
The marquise cut is a variation of the round brilliant cut, which has been stretched out into an oval with pointed ends. This particular cut is considered to be one of the most unique yet sophisticated types of cuts.