3.66 cts Natural Oval-cut Yellow VS1 Zircon (Cambodia)
New without Tags. This gem has never been used/placed/set in a setting.
It is utterly undamaged, unmarred and in perfect condition as expected of NWOTags.
I have included a Zircon article below for your appreciation and enjoyment.
Summary from below: "Zircon is not a very well-known gemstone, but it is one of the most important gemstones of today. Many people confuse zircon with the artificial diamond simulant, cubic zirconia. Of course, the two are completely different - cubic zirconia (CZ), is a lab-created synthetic material, while zircon is a naturally occurring gemstone with a very different chemical composition." ... "Zircon occurs in a wide range of colors, of which white or colorless is likely the least valuable or important." ... "Golden-yellow zircon is sometimes heated."
Type: Natural Zircon (personally confirmed as Genuine High Zircon by digital refractometer (RI=1.982), dichroscope, polariscope, spectroscope, UV short&long-wave light, measured Specific Gravity=4.44) -- captej2012
Color: Yellow
Shape: Oval-cut
Dimensions: 9.20mm x 6.90mm x 5.10mm
Weight: 3.66 ct
Luster: Unbelievable TopFire (as expected of every genuine Zircon)
Clarity: VS1 (w/10X loupe, there are few discernible inclusions; the few seen proves this is natural)
Hardness: 7.5 rating on the Mohs Scale
Treatment: Heated and Not Enhanced
Origin: Cambodia
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Zircon is not a very well-known gemstone, but it is one of the most important gemstones of today. Many people confuse zircon with the artificial diamond simulant, cubic zirconia. Of course, the two are completely different - cubic zirconia (CZ), is a lab-created synthetic material, while zircon is a naturally occurring gemstone with a very different chemical composition. However, before the introduction of diamond simulants like cubic zirconia and moissanite, white zircon was actually one of the most popular diamond substitutes, owing to its high dispersion and refractive index, and was often marketed under the misleading trade name of 'Matura diamond'. Zircon is also remarkably dense and exhibits a very pronounced level of birefringence. Zircon has such high birefringence that it may appear fuzzy or display facet-doubling.
Zircon occurs in a wide range of colors, of which white or colorless is likely the least valuable or important. The most popular zircon today is blue zircon, usually occurring with green pleochroism, which can result in interesting teal-like colors. Blue zircon is actually produced by heating more commonly occurring brown zircon. However, only some brown materials have the appropriate physical structure to turn blue when heated, typically only deposits found in South East Asia - which is why most blue zircon comes from Cambodia or Burma. Blue zircon is one of the traditional modern birthstones for December.
Zircon is a tremendously important mineral, indeed its prominence led to the emergence of the discipline of 'zirconology' in gemology. It is the oldest mineral on Earth, with samples found in Australia that are over 4.4 billion years old. Scientists discovered that zircon actually contains trace elements of uranium and thorium, both of which are elements with known half-lives. It is the uranium and thorium that cause such tremendous variations in the physical properties of zircon. Zircon is typically classified as low, medium and high zircon, in reference to the presence of optical properties. Low zircon has higher traces of radioactive uranium and thorium, which causes an alteration in physical structure, rendering it near-amorphous, though its physical appearance remains the same as high or medium zircon. Low zircon is typically green to brownish in color. Green zircon is rarely seen in the gem trade and is highly sought after.
| Identifying Zircon |
Zircon is a zirconium silicate by composition. An unusual trait with zircon is that its gemological properties exhibit very wide ranges, such as hardness ratings spanning from 6.5 to 7.5 on the Mohs scale. Zircon can also be easily distinguished by its notable birefringence; when looking down through the table of a stone, the doubling effect of facet edges can be easily seen. It also has a relatively high refractive index ranging from 1.810 to 2.024, and a density that can range between 3.93 and 4.73. Zircon also has a relatively high dispersion rating, exhibiting fire and brilliance comparable to that of fine diamond. Many stones will also exhibit strong pleochroism.
Zircon is actually the oldest known mineral on earth; the oldest samples are even older than the moon, which formed about 4 billion years ago. Zircon was the first crystal to form in molten granite as it cooled to form rock. Low zircon formed as the result of a process associated with the presence of uranium and thorium. The natural radioactivity disrupts the crystal structure and produces the changes in color and density through a process known as metamictization.
Most zircon deposits are alluvial. Sri Lanka is the best known source for green metamict 'low' zircon. Specimens are also found in Burma (Myanmar), and may possibly exist in other well-known zircon deposits in Cambodia. Most zircon deposits come from Burma, though Australia boasts the oldest deposits dating back more over 4.4 billion years. Other notable sources include Brazil, Korea, Madagascar, Mozambique, Nigeria, Tanzania, Thailand and Vietnam.
Zircon Color
Zircon in its purest form is completely colorless (white), but owing to trace impurities, it can occur in a wide range of interesting colors, including yellow, orange, red, green, blue, violet, brown and combinations in between. Yellow-brown to orange and red zircon are the most common occurrences, along with colorless. Blue is the most popular, but its color is obtained through the heating of brown zircon, usually from Cambodia and Burma. Due to pleochroism, blue zircon can look greenish from certain angles. Medium dark, pure blue stones have the most value. Green zircon is very rare and typically very expensive.
Zircon Clarity and Luster
In general, zircon is transparent to translucent. Impurities cause the various colors. Zircon with cat's eye chatoyancy is known but very rare. Some crystals contain radioactive elements of thorium and uranium. Over time, the radioactivity breaks down the crystal structure so that such stones tend to a near-amorphous structure, with a slightly lower luster than the crystalline form. These low green zircon specimens are rare and are highly prized by gem collectors. They pose no radioactive heath threat. Zircon exhibits a brilliant, vitreous sheen when polished.
Zircon Cut and Shape
The high birefringence of zircon makes it necessary for the cutter to orient the table of the stone to the optic axis; otherwise the interior may look fuzzy, due to facet image doubling. Colorless stones are most often brilliant cut. Colored stones are most often brilliant or emerald step cut. Round stones are often given a 'zircon cut', which is similar to a standard round brilliant cut, but with an extra row of facets at the edges. The most popular shapes include ovals, rounds, pears, octagons (emeralds) and fancy trillions. Small melees are also popular.
Zircon Treatment
Many zircon stones are completely untreated. Some brown varieties, mostly found in Southeast Asia, may be heated to produce colorless and blue zircon. These colors aren't necessarily stable, since ultraviolet rays or sunlight can cause color loss or changes. Some colors are unenhanced, including rose and rose-orange zircon from Tanzania, and orange to orange-brown zircon from Cambodia. Green zircon is very rare and owes its color to minute natural traces of uranium and thorium. Golden-yellow zircon is sometimes heated.