By Ruby Butcher
By Ben Collinson
Cubic zirconia (or CZ) is the cubic crystalline form of zirconium dioxide (ZrO2). The synthesized material is hard, optically flawless, and usually colourless, but it can be produced in a variety of different colours. It should not be confused with zircon, which is zirconium silicate (ZrSiO4).
Given its low cost, durability, and close visual likeness to diamond, synthetic cubic zirconia has remained the most gemologically and economically important competitor for diamonds since 1976. It is marketed as a "diamond simulant." Its main competition as a synthetic gemstone is the more recently cultivated material, synthetic moissanite.
Cubic Zirconia Versus Diamond
A few key features of cubic zirconia distinguish it from diamond. Some of these are observable only under a microscope or loupe. Examples are noted below.
- Dispersion: With a dispersive power greater than diamond (0.060 vs. 0.044), the more prismatic fire of cubic zirconia can be recognized even by an untrained eye.
- Hardness: As noted above, cubic zirconia has a hardness of 8.5 to nearly 9.0 on the Mohs hardness scale, whereas the rating for diamonds is 10.
- Specific gravity: Cubic zirconia crystals are heavyweights compared to diamonds. A cubic zirconia crystal will weigh about 1.7 times more than a diamond of equivalent size.
- Flaws: Contemporary methods allow the production of virtually flawless crystals of cubic zirconia. By contrast, most diamonds have some sort of defect, be it a feather, included crystal, or perhaps a remnant of an original crystal face (for example, trigons).
- Refractive index: Cubic zirconia has a refractive index of 2.176, compared to a diamond's 2.417.
- Cut: Under close inspection with a loupe, the facet shapes of some cubic zirconia appear different from diamonds.
- Colour (or more precisely, the lack thereof): Only the rarest of diamonds are truly colourless, most having a tinge of yellow or brown to some extent. By comparison, cubic zirconia can be made in most cases entirely colourless: equivalent to a perfect "D" on diamond's colour grading scale.
- Thermal conductivity: Cubic zirconia are thermal insulators while diamonds are among the most efficient thermal conductors, exceeding copper. This makes telling the difference between diamond and cubic zirconia quite easy for those with the right instruments.
- Visually, it can be challenging to tell exceptionally- cut CZ’s apart from authentic diamonds. There are many high-quality best diamond simulate products to choose from, making this all the more compelling. The list of prestigious companies that sell this stone all possess brand-specific registered trade mark names for the diamond stimulants, most often being made of cubic zirconia.
- Jewellers use equipment like loupes and magnifiers to identify gemstones. A loupe is a small hand held lens that magnifies a gemstone to great detail allowing gemmologists and professionals to identify small fine points. Zirconia do not possess inclusions so this is one way to differentiate the two.
Russia developed cubic zirconia gemstones to create a specialized window glass for their space program to function and allow cosmonauts to take pictures through the window. The world’s first CZ was made in the USSR. It was manufactured to compose a gemstone with the similar optical properties of a ruby and was intended to be used in Russian laser technology. It was not used in jewellery until 1969 when a creative person decided to facet the material.
Cubic zirconia is an impressive diamond simulant that offers unsurpassed quality and price. The dispersion of white light from a CZ is superior at 0.058-0.066 to a diamond’s 0.044. CZ is a truly colourless gem, equivalent to a perfect D on the diamond-colour grade scale and by comparison delivers a generally indistinguishable product.
Diamonds are always best worn with other stones and are associated with Crown Chakra, or the colour of white. Chakra is an Indian philosophy that designates energy centres in our bodies. The purpose of the Crown Chakra is to connect spirituality to the physical being and encourage intuitive knowing. Zircon on the other hand is said to communicate with angels and provide safe passage upon travel.