Zircons are rare minerals with a wide variety of colors. Some gems come in golden-yellow, red, brown, yellowish-green and sky-blue colors. The color palette of minerals is created by admixtures of different metals, such as iron, copper, zinc, calcium or titanium. Natural zircons are small, pointed crystals with a regular edge.
Hyacinths – are distinguished by their orange, brownish-red, and golden-red coloring. These stones are valued by the experts. Hyacinths that are on the jewelry market do not usually weigh more than 5 carats.
Jargons are characterized by their straw-yellow color and are extremely rare.
Zircons are green, lilac, pink and brown in color.
Other zircons are often found with rare color-changing effects.
Dispersion is the play of colored flashes in the stone. Zircon's dispersion index is very high, higher than that of diamond, which makes it extremely attractive for jewelry making. Natural zircons exhibit stunning fire and iridescent flashes, which is why colorless, transparent zircons are sometimes used as substitutes for diamonds.
Birefringence is the effect of bifurcation; in zircons, it is very strong and can be seen with the naked eye. Birefringence can give the impression of a bifurcated image of a stone in a photograph. The bifurcation effect helps to distinguish a zircon from a number of other colored stones.
Cat's eye effect is a very rare optical effect for zircons. It is characteristic of cabochon-cut stones with longitudinal inclusions that create a stripe of light on the surface of the stone. The stripe moves when the stone is shaken.
Transparent colorless zircons are characterized by a high index of refraction and strong dispersion. When these stones are cut well, they resemble diamonds. They sparkle under the rays of light that fall on their facets. The play of light is more noticeable in the pale crystals. Stones of darker shades play worse.
The gemological uniqueness of zircons consists of a considerable variation of density and light refraction, which goes far beyond the results attributed to differences in the chemical composition or to the presence of voids in the crystal structure.
Experts consider zircon one of the most undervalued gems on the market and predict an increase in value. The precious zircon is yet to reach its maximum market potential; we believe it has only a few years left. Already we see an increase in demand for this stone not only among collectors but also among big-name jewelry houses that release limited editions and collections with this beautiful gemstone. Zircon jewelry from the German company Hemmerle is famous all over the world.
Prices for zircons vary in color varieties, but the main pricing factors are: the weight of the stone, clarity, cut and most importantly - the degree of saturation of color. The most expensive variety is the blue Cambodian zircons. Large rich-blue, almost blue, quality-cut samples may cost $280-450 per carat. Lighter coloring ranges from $150 to $280 per carat. Yellow, red, brown, and colorless zircons cost an average of $100-200 per carat.
Jewelry zircon is mined only in a few fields. The best minerals come from Cambodia and Sri Lanka. The gems from these countries have the most diverse color palette that includes instances of a reddish-brown, yellow and green. Interestingly, all Starlite arrive on the market exclusively from Cambodia. Most of the gems becomes colorless color after refining by heat treatment. Along with this produces a small amount of natural colorless zircons in the area called Matara in southern Sri Lanka. Gem of good quality is mined in the deposits in Burma, Thailand, Tanzania, Madagascar and Vietnam.
Note that the zircon blue, Golden-yellow and colourless crystals, which is now at the peak of popularity are sanitized reddish-brown minerals from Cambodia. Interestingly, the results of heat treatment of the crystals are highly resistant.
The raw material of zircon is brown or, less frequently, orange in color. Zircon mined material acquires a blue color after being annealed in special furnaces. The color of zircons changes color to colorless, yellow, or orange after heating. Mineral zircons are heat-treated for over 90% of their color. Thermal treatment of zircons is generally accepted by the gemological community and does not affect their value, similar is the case with tanzanites. Heating takes place in a homemade box furnace, where a refractory container with raw material is placed. The container protects the crystals from direct flame, which prevents the raw material from cracking. The process takes only a few hours. Sometimes the crystals are heated in two steps to correct their color. The color change as a result of annealing is stable.
The rare natural stone zircon, because of the similarity in name, is often confused with cubic zirconium (cubic zirconia), a cheap synthetic stone that is used as an imitation of a diamond. This is not the only name confusion that arises among buyers. Zircon is also confused with the similar-sounding zirconium, which is indicated as Zr in the Mendeleev table.
Zircon (ZrSiO4) is a natural gemstone.
Cubic Zirconia is a fianite, a synthetic imitation of a diamond.
Zirconium (Zr) is a metal from the Mendeleev table.
Jewelry with zircons from German company Hemmerle and other lesser-known brands are known all over the world. The designers of the jewelry houses make exclusively exclusive pieces.