 A round brilliant-cut cubic zirconia Cubic zirconia (or CZ), the cubic crystalline form of zirconium dioxide (ZrO2), is a mineral that is widely synthesized for use as a diamond simulant. 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). Cubic zirconia is extremely rare in nature. Photo of a round brilliant-cut cubic zirconia by Gregory Phillips. ...
General Name, Symbol, Number zirconium, Zr, 40 Chemical series transition metals Group, Period, Block 4, 5, d Appearance silvery white Standard atomic weight 91. ...
An oxide is a chemical compound containing an oxygen atom and other elements. ...
Zirconium dioxide (ZrO2), sometimes known as zirconia, is a white crystalline oxide of zirconium. ...
For other uses, see Mineral (disambiguation). ...
Due to its low cost and close visual likeness to diamond, cubic zirconia has remained the most gemologically and economically important diamond simulant since 1976. ...
Zircon is a mineral belonging to the group of nesosilicates. ...
In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ...
Because of its low cost, durability, and close visual likeness to diamond, synthetic cubic zirconia has remained the most gemologically and economically important diamond simulant since 1976. Its main competition as a synthetic gemstone is the more recently cultivated material, synthetic moissanite. This article is about the mineral. ...
Gemology (gemmology outside the United States) is the science, art and profession of identifying and evaluating gemstones. ...
Year 1976 Pick up sticks(MCMLXXVI) was a leap year starting on Thursday (link will display full calendar) of the Gregorian calendar. ...
For other uses, see Gemstone (disambiguation). ...
Moissanite is a trade name given to silicon carbide (chemical formula SiC) for use in the gem business. ...
Technical aspects As its name would imply, cubic zirconia is crystallographically isometric, and as diamond is also isometric, this is an important attribute of a would-be diamond simulant. Synthesized material contains a certain mole percentage (10-15%) of metal oxide stabilizer. During synthesis zirconium oxide would otherwise form monoclinic crystals, its stable form under normal atmospheric conditions. The stabilizer is required for cubic crystal formation; it may be typically either yttrium or calcium oxide, the amount and stabilizer used depending on the many recipes of individual manufacturers. Therefore the physical and optical properties of synthesized CZ vary, all values being ranges. Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in solids. ...
In crystallography, the cubic crystal system (or isometric crystal system) is the most symmetric of the 7 crystal systems. ...
The mole (symbol: mol) is the SI base unit that measures an amount of substance. ...
This article is about metallic materials. ...
In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. ...
For other uses, see Crystal (disambiguation). ...
General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ...
For other uses, see Calcium (disambiguation). ...
It is a dense substance, with a specific gravity between 5.6–6.0. Cubic zirconia is relatively hard, at about 8.5 on the Mohs scale—nowhere near diamond, but much harder than most natural gems. Its refractive index is high at 2.15–2.18 (B-G interval) and its luster is subadamantine. Its dispersion is very high at 0.058–0.066, exceeding that of diamond (0.044). Cubic zirconia has no cleavage and exhibits a conchoidal fracture. It is considered brittle. Relative density (also known as specific gravity) is a measure of the density of a material. ...
Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ...
For other uses, see Gemstone (disambiguation). ...
The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ...
For the file system called Lustre, see Lustre (file system) Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock or mineral. ...
Dispersion of a light beam in a prism. ...
Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types: Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes. ...
Conchoidal fracture describes the way that brittle materials break when they do not follow any natural planes of separation. ...
Under shortwave UV cubic zirconia typically luminesces a yellow, greenish yellow or "beige". Under longwave UV the effect is greatly diminished, with a whitish glow sometimes being seen. Colored stones may show a strong, complex rare earth absorption spectrum. Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ...
Luminescence is light not generated by high temperatures alone. ...
Rare earth ore Rare earth elements and rare earth metals are trivial names sometimes applied to a collection of 17 chemical elements in the periodic table, namely scandium, yttrium, and the lanthanides. ...
A materials absorption spectrum shows the fraction of incident electromagnetic radiation absorbed by the material over a range of frequencies. ...
History Discovered in 1892, the yellowish monoclinic mineral baddeleyite is a natural form of zirconium oxide. It has little economic importance because of its rarity. 1892 (MDCCCXCII) was a leap year starting on Friday (see link for calendar). ...
Baddeleyite is a mineral that consists of zirconia (ZrO2). ...
The extremely high melting point of zirconia (2750°C) posed a hurdle to controlled single-crystal growth, as no existing crucible could hold it in its molten state. However, stabilization of zirconium oxide had been realized early on, with the synthetic product stabilized zirconia introduced in 1930. Although cubic, it was in the form of a polycrystalline ceramic: it was made use of as a refractory material, highly resistant to chemical and thermal (up to 2540°C) attack. For other uses, see Crucible (disambiguation). ...
]]s are polycrystalline. ...
Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεÏαμικός (keramikos). ...
The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ...
Seven years later, German mineralogists M. V. Stackelberg and K. Chudoba discovered naturally occurring cubic zirconia in the form of microscopic grains included in metamict zircon. Thought to be a byproduct of the metamictization process, the two scientists did not think the mineral important enough to formally name. The discovery was confirmed through x-ray diffraction, proving the existence of a natural counterpart to the synthetic product. Mineralogy is an earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. ...
Metamictization (sometimes called metamiction) is a natural process resulting in the gradual and ultimately complete destruction of a minerals crystal lattice, leaving the mineral amorphous. ...
X-ray crystallography is a technique in crystallography in which the pattern produced by the diffraction of x-rays through the closely spaced lattice of atoms in a crystal is recorded and then analyzed to reveal the nature of that lattice. ...
As with the majority of grown diamond look-alikes, the conceptual birth of single-crystal cubic zirconia began in the minds of scientists seeking a new and versatile material for use in lasers and other optical applications. Its evolution would eclipse earlier synthetics, such as synthetic strontium titanate, synthetic rutile, YAG (Yttrium Aluminium Garnet) and GGG (Gadolinium Gallium Garnet). For alternative meanings see laser (disambiguation). ...
Strontium titanate is an oxide of strontium and titanium with the chemical formula SrTiO3. ...
Rutile is a mineral composed primarily of titanium dioxide, TiO2. ...
YAG Yttrium Aluminum Garnet Color: Wide range of colors Moh’s hardness: 8. ...
General Name, Symbol, Number yttrium, Y, 39 Chemical series transition metals Group, Period, Block 3, 5, d Appearance silvery white Standard atomic weight 88. ...
Aluminum redirects here. ...
Garnet is a group of minerals that have been used since the Bronze Age as gemstones and abrasives. ...
Gadolinium Gallium Garnet (GGG, Gd3Ga5O12) is a synthetic crystalline material of the garnet group, with good mechanical, thermal, and optical properties. ...
General Name, Symbol, Number gadolinium, Gd, 64 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 157. ...
General Name, Symbol, Number gallium, Ga, 31 Chemical series poor metals Group, Period, Block 13, 4, p Appearance silvery white Standard atomic weight 69. ...
Some of the earliest research into controlled single-crystal growth of cubic zirconia occurred in 1960s France, much work being done by Y. Roulin and R. Collongues. This technique involved molten zirconia being contained within a thin shell of still-solid zirconia, with crystal growth from the melt: The process was named cold crucible, an allusion to the system of water cooling used. Though promising, these pursuits yielded only small crystals.
Later, Soviet scientists under V. V. Osiko at the Lebedev Physical Institute in Moscow perfected the technique, which was then named skull crucible (an allusion either to the shape of the water-cooled container or to the occasional form of crystals grown). They named the jewel Fianit, but the name was not used outside of the USSR. Their breakthrough was published in 1973, and commercial production began in 1976. By 1980 annual global production had reached 50 million carats (10,000 kg). CCCP redirects here. ...
The Lebedev Physical Institute of the Russian Academy of Sciences is a Russian research institute specializing in physics. ...
For other uses, see Moscow (disambiguation). ...
The Skull Crucible process was developed at the Lebedev Physical Institute in Moscow to manufacture cubic zirconia. ...
The carat is a unit of mass used for gems, and equals 200 milligrams or 3. ...
Synthesis
 A worker monitoring melting zirconium oxide in a furnace to create cubic zirconia. The Soviet-perfected skull crucible is still used today, with little variation. Water-filled copper pipes provide a cup-shaped scaffold in which the zirconia feed powder is packed, the whole contraption being wrapped with radio frequency induction coils running perpendicular to the copper pipes. A stabilizer is mixed with the feed powder, being typically either yttria or calcium oxide. Image File history File linksMetadata 1000kwCZLpKelley. ...
Image File history File linksMetadata 1000kwCZLpKelley. ...
For other uses, see Copper (disambiguation). ...
Radio frequency induction or RF induction is an electrical phenomenon in which an electromagnetic wave passing through a conductor causes electric current to flow through it. ...
The RF induction coils function in a manner similar to the primary winding in a transformer. The zirconia acts as the "secondary winding" of a transformer which in effect is "shorted" out and thus gets hot. This heating method requires the introduction of small pieces of zirconium metal. The metal is placed near the outside of the charge and is melted by the RF coils and heats the surrounding zirconia powder from the outside inwards. The cooling water-filled pipes embracing the outer surface maintain a thin "skin" (1-2 mm) of unmelted feed, creating a self-contained apparatus. After several hours the heat is reduced in a controlled and gradual manner, resulting in the formation of flawless columnar crystals. Prolonged annealing at 1400°C is then carried out to remove any strain. The annealed crystals, which are typically 5 cm long by 2.5 cm wide (although they may be grown much larger), are then cut into gemstones. For other uses, see Annealing. ...
The addition of certain metal oxide dopants into the feed powder results in a variety of vibrant colors. For example: A dopant, also called doping agent and dope, is an impurity element added to a semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor. ...
General Name, Symbol, Number cerium, Ce, 58 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 140. ...
General Name, symbol, number chromium, Cr, 24 Chemical series transition metals Group, period, block 6, 4, d Appearance silvery metallic Standard atomic weight 51. ...
General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Standard atomic weight 144. ...
General Name, Symbol, Number erbium, Er, 68 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Standard atomic weight 167. ...
General Name, symbol, number titanium, Ti, 22 Chemical series transition metals Group, period, block 4, 4, d Appearance silvery metallic Standard atomic weight 47. ...
Innovations In recent years manufacturers have sought ways of distinguishing their product by supposedly "improving" cubic zirconia. Coating finished CZs in a film of diamond-like carbon (DLC) or Amorphous Diamond is one such innovation, a process using chemical vapor deposition. The resulting material is purportedly harder, more lustrous and more like diamond overall: The coating is thought to quench the excess fire of CZ, while improving its refractive index, thus bringing it more in line with diamond. Additionally, because of the high percentage of diamond bonds in the amorphous diamond coating, the finished simulant will show a positive diamond signature under Raman spectroscopy. Diamond-like carbon (DLC) is an umbrella term that refers to 7 forms[1] of amorphous carbon materials that display some of the unique properties of natural diamond. ...
DC plasma (violet) enhances the growth of carbon nanotubes in this laboratory-scale PECVD apparatus. ...
This article or section does not cite any references or sources. ...
Another technique first applied to quartz and topaz has also been adapted to cubic zirconia: Vacuum-sputtering an extremely thin layer of metal oxide (typically gold) onto the finished stones creates an iridescent effect. This material is marketed as "mystic" by many dealers. Unlike DLC, the surreal effect is not permanent, as abrasion easily removes the oxide layer. For other uses, see Quartz (disambiguation). ...
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO4(F,OH)2. ...
GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ...
The iridescence of the Blue Morpho butterfly wings. ...
Cubic Zirconia versus Diamond Cubic zirconia is so optically close to diamond that only a trained eye can easily differentiate the two. There are a few key features of CZ which distinguish it from diamond, some observable only under the microscope or loupe. For example: Robert Hookes microscope (1665) - an engineered device used to study living systems. ...
A magnifying glass A magnifying glass is a single convex lens which is used to produce a magnified image of an object. ...
- Dispersion. With a dispersive power greater than diamond (0.060 vs. 0.044) the more prismatic fire of CZ can be seen by even an untrained eye.
- Specific gravity. CZs are heavyweights in comparison to diamonds; a CZ will weigh about 1.7 times more than a diamond of equivalent size.
- Flaws. Contemporary production of cubic zirconia is virtually flawless, whereas most diamonds have some sort of defect, be it a feather, included crystal, or perhaps a remnant of an original crystal face (e.g. trigons).
- Refractive index. CZ 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 CZs appear different from diamonds.
- Color. More precisely, the lack of color: Only the rarest of diamonds are truly colorless, most having a tinge of yellow or brown to some extent. By comparison, CZ can be made in most cases entirely colorless: equivalent to a perfect "D" on diamond's color grading scale.
- Thermal conductivity. CZs are thermal insulators while diamonds are among the most efficient thermal conductors, exceeding copper. This makes telling the difference between diamond and CZ quite easy for those with the right instruments.
Dispersion of a light beam in a prism. ...
If a shaft of light entering a prism is sufficiently narrow, a spectrum results. ...
This article or section does not cite any references or sources. ...
Relative density (also known as specific gravity) is a measure of the density of a material. ...
The term Trigon may refer to several things: A three-sided ancient Greek or Roman lyre. ...
The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ...
A magnifying glass A magnifying glass is a single convex lens which is used to produce a magnified image of an object. ...
Jewelers diamonds in groups of similar colors. ...
K value redirects here. ...
See also This article is about the mineral. ...
Due to its low cost and close visual likeness to diamond, cubic zirconia has remained the most gemologically and economically important diamond simulant since 1976. ...
A collection of colorless cultured diamonds grown by Apollo Diamond, Inc. ...
Jewellery (Jewelry in American spelling) comprises ornamental objects worn by persons, typically made with gemstones and precious metals. ...
Further reading - Nassau, Kurt (1980). Gems Made by Man. ISBN 0-8019-6773-2.
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