Cubic Zirconia

Cubic Zirconia, often abbreviated as CZ, is a synthetic gemstone that has gained popularity as a brilliant and affordable alternative to natural diamonds. Its name stems from its crystal structure, which is cubic in nature, closely resembling the crystal lattice of diamond.

Cubic Zirconia is created in laboratories through a meticulous process that involves melting zirconium oxide and yttrium oxide at extremely high temperatures and then cooling it to form colourless, flawless crystals. This synthetic gemstone can also be crafted in various colours by adding trace elements to the crystal mixture.

While it is not found in nature, the appeal of Cubic Zirconia lies in its diamond-like sparkle and affordability, making it a popular choice for jewellery, particularly as a diamond simulant. Its introduction in the 1970s revolutionized the gemstone market, offering an accessible option for those seeking brilliant, sparkly jewellery without the cost associated with natural diamonds.

Click on the terms in the table below to discover their meaning

Image of faceted Cubic Zirconia — Faceted Cubic Zirconia by James St. John (used under CC BY 2.0 licence)

Image of faceted teal Cubic Zirconia — Faceted teal Cubic Zirconia by Michelle Jo (used under CC BY 3.0 licence)

Image of faceted multicoloured composite Cubic Zirconias — Faceted multicoloured composite Cubic Zirconias by Michelle Jo (used under CC BY 3.0 licence)

Click on the terms in the table below to discover their meaning

Name	Cubic Zirconia
Category	Oxide mineral
Chemical Formula	ZrO₂
Chemical Formula
IMA Symbol	Not approved
Crystal System	Cubic (Isometric)
Crystal Habit	Granular in natural crystals; columnar in synthetic crystals
Twinning	Absent
Cleavage	None
Fracture	Conchoidal
Tenacity	Brittle
Hardness (Moh's Scale)	8 - 8.5
Specific Gravity	5.5 - 6.0
Diaphaneity	Transparent to opaque
Colour	Can be synthesised in any colour
Streak	White
Lustre	Sub-adamantine
Optical Class	Isotropic
Refractive index	n = 2.150 - 2.180


Birefringence	Absent
Dispersion	Rd = 0.060
Pleochroism	Absent


Clarity	Type I
Notable Varieties	Synthetic Cubic Zirconia

References

Hansen, R. (2022). Gemstones: A Concise Reference Guide. Clayton: CSIRO Publishing.

Schumann, W. (2013). Gemstones of the World (17th ed.). (D. Shea, & N. Shea, Trans.) New York: Stirling Publishing Company.

About the Author

Daniel Gillespie is student of Web Development and the developer of Gemology 101. With a straightforward and informative approach, Daniel invites readers to explore the world of gemology, offering a valuable resource for both enthusiasts and those seeking knowledge about precious stones.