Cubic Zirconia

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Cubic Zirconia (abbreviated CZ) is the best-known man-made diamond simulant. A simulant is any material, natural or created by man, which imitates the appearance of a natural gem whereas a synthetic gem is man-made but must have a natural counterpart that duplicates the chemical, optical, and physical properties of the natural gem. While it's often touted as the most popular diamond simulant, cubic zirconia is also a synthetic gem. Natural crystals of cubic zirconia have only been found as inclusions in zircon.

Cubic Zirconia Polished
Cubic Zirconia Classification
Common Name Cubic Zirconia
Species Cubic Zirconia
Cubic Zirconia Optical Properties
Transparency Transparent - Opaque
Dispersion Strength: Strong Fire Value: 0.060
Refractive Index Over The Limit 2.150-2.182
Optic Character NA
Polariscope Reaction Aggregate (AGG), Singly Refractive (SR)
Fluorescence SWUV: varies with colorcolorless: yellow or greenish yellowtranslucent pink: weak to moderate, chalky light yellow-green translucent white: very light pink
LWUV: varies with colorcolorless: greenish yellow or yellow-orangetranslucent pink: strong yellow-greentranslucent white: inert
CCF Reaction Translucent white: yellowish green; Translucent black: dark red
Pleochroism None
Cubic Zirconia Characteristic Physical Properties
Hardness 8-8.5
Specific Gravity 5.600-6.000 Typical:5.800
Toughness Good
Inclusions Cubic zirconia is type I clarity stone. Stones are often free of inclusions but might have gas bubbles or zirconium oxide remnants. Translucent stones are uniform in color in reflected light and banded or striped in strong transmitted light.
Luster SubAdamantine
Fracture Conchoidal
Cleavage None
Cubic Zirconia Chemistry & Crystallography
Chemical Name zirconium oxide
Chemical Formula ZrO2
Crystal System Cubic
Chemistry Classification Oxide

Cubic Zirconia Colors

  • Bi-color Cubic Zirconia Bi-color
  • Yellow Cubic Zirconia Yellow
  • White Cubic Zirconia White
  • Red Cubic Zirconia Red
  • Purple Cubic Zirconia Purple
  • Pink Cubic Zirconia Pink
  • Orange Cubic Zirconia Orange
  • Multi-color Cubic Zirconia Multi-color
  • Green Cubic Zirconia Green
  • Gray Cubic Zirconia Gray
  • Colorless Cubic Zirconia Colorless
  • Brown Cubic Zirconia Brown
  • Blue Cubic Zirconia Blue
  • Black Cubic Zirconia Black

Cubic Zirconia Spectra

Cubic Zirconia Spectra

Color possibly due to rare earths. This rather pale lavender blue CZ did not produce the expected strong rare earth spectrum seen in others of a similar color. On close inspection apart from the moderate absorption from 560nm. to 600nm. other weak lines are seen in the deep blue, green and orange.

Cubic Zirconia Spectra

Color due to rare earth elements. In the yellow three extremely faint and narrow lines with one in the orange. With weaker lines in the blue

Cubic Zirconia Spectra

Color due to rare earth elements. Only red & orange light is transmitted down to about 580nm. A group of lines due to neodymium is seen central at 590, along with a single sharp line at 684nm

Cubic Zirconia Spectra

Color due to rare earth elements. Broad absorption from violet into the green

Cubic Zirconia Spectra

Color due to neodymium. The main group of complex absorption lines and bands within the orange yellow in the green.

Cubic Zirconia Spectra

Color due to neodymium. The main group of complex absorption lines and bands within the orange yellow in the green

Cubic Zirconia Spectra

Color due to erbium The striking sharpness and intensity of the absorption lines in this spectrum is typical of this material when doped with the rare earth erbium. The dominant pair of lines in the green at 518nm and 524nm. are immediately evident, both of which are composed of several closely packed lines. The other lines in the violet, blue and red areas are usually distinct.

Cubic Zirconia Spectra

Color due to rare earths. Strong sharp absorption lines of various widths which appear progressively stronger to the right, ending in a sharp edge. Located in the red, green, blue and violet areas depict a typical rare earth spectrum

Cubic Zirconia Spectra

Color due to erbium and neodymium. Often used as a tanzanite simulant this color in CZ is derived by a combination of two rare earth elements. The main absorption lines due to erbium can be seen at 485/490nm; 520/525nm. and a vague group centered at 650nm. The wide group of lines appearing as a diffused band between 570nm. and 605nm. in the yellow area is due to neodymium. Several other lines may be seen in the violet- blue area which may be due to either of these rare earths. Lack of pleochroism and the rare earth spectrum reveals its true nature.

Jewelry Television acknowledges the significant scientific contributions of John S Harris, FGA to the study of gemstone spectra and with deep appreciation to him, acknowledges the use of his images and related notes about gemstones and their spectra in the educational materials on this website.

Alternate Names

CZ, Cubic Z, Diamond-Z, Diamonair II, Diamononesque, Diamonite, Djevalite, Phianite, C-Ox, Pearl CZ

Countries of Origin

Tanzania, United Republic Of; Austria; United States of America (the); Unknown; Sri Lanka; China; Namibia; Russian Federation (the); Australia; Thailand; Switzerland; India


Normal care for untreated stones. In coated stones color may be affected by polishing, recutting, ultrasonic cleaners, alcohol, and harsh chemicals. Coating can be scratched.

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Tim Matthews


Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.