Cubic zirconia is one of the gems people consider a potential alternative to a diamond. Its low cost, durability and visual likeness to the real thing make cubic zirconia gemstones an economically important competitor for diamonds since their production began in 1976.
History of Cubic Zirconia
Cubic zirconia, also known as CZ, is a synthetic gemstone used as an alternative to diamonds. It is the crystalline form of zirconium dioxide, which is a hard, flawless and usually colourless material but may come in a variety of colours. Cubic zirconia can be found in nature as minute crystals within zircon and baddeleyite, although it is extremely rare. All CZ stones available on the market today are man-made, meaning they are created exclusively in laboratories.
The history of cubic zirconia is relatively new, tracing back to 1892 when the mineral baddeleyite, a natural form of zirconium oxide, was discovered. In 1937, German mineralogists M.V. Stackelberg and K. Chudoba discovered naturally occurring cubic zirconia within a zircon. However, the two scientists did not think the mineral was significant enough to give it a formal name. The discovery was later confirmed through x-ray examination, proving the existence of a natural form of cubic zirconia.
The idea of producing synthetic cubic zirconia arose when scientists were looking for a versatile material with a high melting point for use in lasers and other optical applications. The first attempt to grow synthetic CZ was in 1960s France, but it gave only small crystals. Later, Soviet scientists perfected the technique and got a jewel named Fianit after the institute they worked in, but the name was not used outside of the USSR.
The commercial production of cubic zirconia began in 1976 due to its diamond-like qualities, low cost and overall durability. CZ began to be mass-produced for jewellery by the CERES Corporation. Other major producers include Swarovski, ICT Incorporated and Taiwan Crystal Company. Today cubic zirconia is one of the most popular gems used as a diamond alternative. Its main competitor as a synthetic gemstone is moissanite.
Cubic Zirconia Colours
As a synthetic gemstone, cubic zirconia comes in a large array of colours, from colourless to black. The wide colour range is caused by colouring agents added to the source powder during the growth process.
If the colouring agent is caesium, the cubic zirconia turns yellow, orange or red depending on the concentration of the microelements. In the case of copper, iron, nickel and titanium, we get yellow, amber and brown colours.
Lilac, violet, purple and blue cubic zirconia is caused by various combinations of cobalt, manganese and neodymium microelements. The pink colour is due to the presence of erbium, europium and holmium, while green is caused due to chromium, thulium and vanadium.
Cubic Zirconia Clarity and Cut
Since cubic zirconia crystals are created in labs, they are usually internally flawless, making them very attractive to many buyers around the world. However, this is also one of the main ways to tell CZ and diamond apart, as no diamond is perfect.
Cubic zirconia has a much lower refractive index (2.17) than a diamond (2.417 – 2.419), which means when cut and polished, it does not show true brilliance and fire because light passes through CZ much differently.
Cubic zirconia can be found in all traditional shapes and cuts, the most popular being round.
The cut quality of cubic zirconia is graded through the A rating system, which only applies to mass-produced machine cut stones. Rated from A or 1A to AAAAA or 5A, 1A is considered the lowest quality of machine-cut CZ, while 5A is the best possible quality. Hand-cut cubic zirconia stones are of much higher quality, which is why they are not graded through the A system. However, it is important to mention that the quality of hand-cut stones depends on the cutter’s technique and experience.
Cubic Zirconia Care and Cleaning
Even though cubic zirconia looks similar to diamond, it is not as hard. The hardness of CZ is 8.25 – 8.50, while diamond rates 10 on the Mohs hardness scale, meaning care should be taken to prevent scratches. It is also recommended to avoid settings that can expose your gem to high pressure, for example, tension setting, as CZ can burst under stress.
Do not wear your cubic zirconia jewellery while playing sports, exercising, gardening or tidying up. Household cleaners usually contain hydrochloric or sulfuric acid, which can cause your gem to lose its shine.
Put your cubic zirconia jewellery on last when dressing. Chemicals from makeup, hairspray, perfume and body creams can change the gemstone’s colour or make it look dull. Putting your jewellery on should always be the last step.
To clean cubic zirconia jewellery at home, use mild dishwashing soap and warm water. Carefully place your jewellery in the liquid and soak it for about 20 – 30 minutes. Next, use a soft toothbrush to remove the dirt. Brush the cubic zirconia jewellery gently not to loosen the prongs, paying particular attention to all sides and edges. Make sure to clean the lower part of the gem as well. The base of the mounting underneath the stone is where a lot of dirt builds up. Rinse your jewellery piece with clean water and dry it with a soft and lint-free cloth.
When storing cubic zirconia, keep it separated from other gems and jewellery. For better protection, wrap them with a soft cloth and place the gems inside a fabric-protected jewellery box to avoid scratches from other harder gemstones.
Cubic Zirconia Properties
|Chemical Name||Zirconium dioxide|
|Colours||Colourless, yellow, orange, amber, brown, pink, red, lilac, violet, purple, green, blue and black|
|Hardness||8.25 - 8.50 on the Mohs scale|
|Refractive Index||2.171 - 2.177|
|Specific Gravity||5.65 - 5.95|
|Fluorescence||Yellow, greenish yellow or beige|
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