THE MINERAL ZIRCON

  • Chemistry: ZrSiO4, Zirconium Silicate
  • Class: Silicates
  • Subclass: Nesosilicates
  • Uses: Gemstone and mineral specimens
  • We sell natural zircon mineral Specimens

Zircon's reputation has suffered of late due to the introduction of a diamond simulant. So for the record, zircon (zirconium silicate, ZrSiO4) is NOT the same material as the artificial gem material Cubic Zirconia (zirconium oxide, ZrO2). However with that in mind, zircon has been used as a diamond simulant both for innocent and nefarious reasons. Zircon resembles diamond in luster and fire and colorless zircons have been mistaken for diamonds by experienced jewelers. Zircon can make a very attractive and affordable gemstone. It is found in browns and greens but can be heat treated to beautiful blue and golden colors. Colorless material is produced in this way as well. Zircon is the December Birthstone.

As a mineral specimen, zircon is uncommon in most rock shops because attractive specimens are rare. However, fine specimens of well shaped zircons are available and are in demand. The typical simple crystal of zircon is a tetragonal prism terminated with four sided pyramids at each end. The prism may be lacking and the crystal can look octahedral. More complex crystals have faces of a less steeply inclined prism that taper the terminations. Also a secondary prism may truncate the primary prism by cutting off its edges and producing an octagonal cross-section through the crystal. There is even an eight sided pyramid (actually a ditetragonal dipyramid) that may modify the four sided pyramids. As you can see, zircon crystals can go from a very simple crystal to a rather complexly faceted form.

PHYSICAL CHARACTERISTICS:

  • Color is brown, red, yellow, green, blue, black, and colorless.
  • Luster is adamantine.
  • Transparency crystals are transparent to translucent.
  • Crystal System tetragonal; 4/m 2/m 2/m
  • Crystal Habits: dipyramidal and prismatic as discussed above.
  • Cleavage indistinct in two directions, prismatic.
  • Fracture is uneven
  • Hardness is 7.5
  • Specific Gravity is 4.6-4.7
  • Streak white
  • Associated Minerals albite, biotite, garnets, xenotime and monazite.
  • Other Characteristics: is sometimes fluorescent and darker crystals may be radioactive due to impurities of rare earth elements. Also index of refraction is 1.92 - 2.01
  • Notable Occurances Seiland, Norway; Pakistan; Russia; Bancroft and Sudbury, Ontario, Canada and New Jersey and Colorado, USA.
  • Best Field Indicators are crystal habit, hardness, luster and density.
ZIRCON specimens:
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ZIRCON specimen zir-5
$ 60.00
Dims: 1.1" x 0.7" x 0.6"(2.8 x 1.8 x 1.5 cm)
Wt: 17.4 g w/ base
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
This specimen basically consists of two tetragonal prismatic Zircon crystals that are not quite completely intergrown, so that one can see that there were originally two crystals. The resulting crystal has a rather warped shape; it actually appears to have been broken and healed over on its underside. Like other Zircons from this locality, it has a brown-red color, adamantine luster, and is opaque. There is only a very small amount of black matrix(I believe that it is epidote) on the crystal, down where the specimen is glued onto its square acrylic base. For all of its flaws, it is an attractive specimen that displays well.
no photo
zir-5 ($ 60.00)
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
ZIRCON specimen zir-8
$ 150.00
Dims: 2.2" x 1.9" x 1.3" (5.6 x 4.8 x 3.3 cm)
Wt: 2.85 oz. (80.8 g)
Nuristan, Afghanistan
I count 6 Zircon crystals in the albite host rock of this Afghani specimen that are 0.1" (3 mm) in diameter or greater; only two of these appear to be undamaged and complete enough for one to see their tetragonal bipyramidal form. However, the larger of these crystals will take all the attention away from the broken ones. It is rather large , measuring 0.7 x 0.5 x 0.5" (1.8 x 1.3 x 1.3 cm), and is in near-perfect condition- I have not seen a Zircon crystal of this size in such good condition before! It is more than 50% exposed, and though there appears to be two natural "gouges" in spots, one of which is partially filled with albite, they are both quite small, and are the only visible imperfections. Its form is really splendid, complete with the acute angles that mark the "terminations" on each end. Though it is only slightly transparent in one or two spots and partially translucent even in sunlight, one can readily see its red-brown coloration due to some internal fractures that are near the surface. There seems to be a very thin film of albite partially covering most of the visible faces that dulls the crystal's adamantine luster, but this is likely not difficult to remove, and I actually took a bit off with a fingernail. Besides the other unbroken crystal (which only measures 1" or 3 mm in diameter) and the broken ones, the albite matrix only houses a bit of black biotite mica. It is an excellent example of a good Zircon crystal.
no photo
zir-8 ($150.00)
Nuristan, Afghanistan
ZIRCON specimen zir-9
$ 45.00
Dims: 1.1 x 1.1 x 0.7" (2.8 x 2.8 x 1.8 cm)
Wt: 24.9 g
Mud Tank, Harbs Range, Northern Territories, Australia
This small thumbnail specimen consists of a single incomplete Zircon crystal. Though it is heavily damaged, almost all of it appears to have occurred prior to mining. What form is intact is very good, with well-defined edges and relatively smooth faces that possess a bright, nearly adamantine luster. It has a rather dark reddish-brown coloration and is dimly translucent in normal light, but shows small patches of transparence. It glows a beautiful bright yellow under shortwave UV light that is brighter than shown in the fluorescent image. There is no host rock present.
no photo
zir-9 ($ 45.00)
Mud Tank, Harbs Range, Northern Territories, Australia
ZIRCON specimen zir-10
$ 40.00
Dims: 1.2 x 0.7 x 0.7" (3.0 x 1.8 x 1.8 cm)
Wt: 19.3 g w/ base
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
At least 6 small Zircon crystals make up the bulk of this thumbnail specimen. They range in size from 0.2 x 0.1 x 0.1" (5 x 3 x 3 mm) to 0.8 x 0.6 x 0.3" (2.0 x 1.5 x 0.8 cm) and are generally in very good condtion- only the two largest crystals show any obvious damage. All are heavily intergrown, so that their form is slightly warped, but they still have good tetragonal form. Their edges are slightly disseminated but still well-defined, and their faces are reasonably clean, possessing a slightly dull adamantine luster. All have a deep red-brown color that is common with Zircons from this locality, and they are completely opaque. The base rock on which they rest appears to be made up of red-colored calcite and either hornblende or epidote, I cannot tell which. Though the base materials are crystalline in nature, they show no definite form. The piece is hot-glued onto an acrylic base.
no photo
zir-10 ($ 40.00)
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
ZIRCON specimen zir-11
$ 60.00
Dims: 2.6 x 2.1 x 0.8" (6.6 x 2.1 x 0.8 cm)
Wt: 4.98 oz. (141.3 g)
Manangi, Darrah Pech, Kunar Province, Afghanistan
Though two Zircon crystals rest in the syenite host rock of this specimen, only one is really worthy of study. The smaller of the two is broken and mostly incomplete, whereas the larger, though damaged, is intact and in moderate to good condition. It has visible dimensions of 0.6 x 0.4 x 0.4" (1.5 x 1.0 x 1.0 cm) and shows good tetragonal prismatic form with well-defined edges and clean faces that possess the standard adamantine luster. It has a deep red coloration with a strong hint of brown and is generally translucent but shows patches of noticeable transparence. The syenite host rock contains two other minerals, only one of which I can identify- it is biotite, and has all of the characteristics of its species. The other material occurs in long, flattened prismatic crystals and has a dark gray coloration and an almost fibrous luster.
no photo
zir-11 ($ 60.00)
Manangi, Darrah Pech, Kunar Province, Afghanistan
ZIRCON specimen zir-12
$ 60.00
Dims: 1.2 x 0.7 x 0.6" (3.0 x 1.8 x 1.5 cm)
Wt: 21.1 g w/ base
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
This thumbnail specimen consists of at least 2 intergrown Zircon crystals. They are both in good condition, showing little damage, and are of nearly equal dimensions, measuring about 0.9 x 0.4 x 0.3" (2.3 x 0.9 x 0.7 cm). Actually, it is difficult to tell whether these are two separate crystals that grew into each other, or if this is a single crystal that twinned in a very odd way. I am thinking that it might be a twinned crystal, as the "two" are arranged exactly parallel to each other. Either way, their tetragonal form is very good. They have the standard red-brown color and nearly adamantine luster of Zircons from this locality, and are essentially opaque. They are accompanied by attached fragments of a black mineral that is most likely hornblende.
no photo
zir-12 ($ 60.00)
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
ZIRCON specimen zir-13
$ 45.00
Dims: 1.3 x 0.7 x 0.6" (3.4 x 1.9 x 1.6 cm)
Wt: 14.2 g
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
This thumbnail specimen consists of an incomplete Zircon crystal. Though incomplete, it shows no human-induced damage and has dimensions of 0.8 x 0.7 x 0.5" (2.0 x 1.7 x 1.3 cm). Its tetragonal prismatic form is very good where intact- its edges are well-defined and its faces are clean, showing a subadamantine luster. Like most specimens from this locality, it has a red-brown color and is opaque, and glows a dim yellow under shortwave ultraviolet light. A few broken bits of what appears to be hornblende are attached,as well as a few grains of a feldspar.
no photo
zir-13 ($ 45.00)
Kipawa Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
ZIRCON specimen zir-14
$ 60.00
Dims: 2.0 x 2.0 x 1.4" (5.1 x 4.0 x 3.5 cm)
Wt: 3.47 oz. (98.4 g)
Kipawa Rare Earth Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
At least 15 small Zircon crystals rest in the syenite host rock of this specimen. They are in moderately good condition, as most are lightly damaged, and reach a maximum diameter of nearly 0.4" (1 cm). All have excellent tetragonal prismatic form, a deep, brick-red color and the standard adamantine luster. All are essentially translucent due to intense internal fracturing. A few bits of what might be biotite are also embedded in the host rock.
no photo
zir-14 ($ 60.00)
Kipawa Rare Earth Complex, Sheffield Lake, Villedieu Township, Quebec, Canada
ZIRCON specimen zir-15
$ 78.00
Dims: 1.1 x 0.6 x 0.5" (2.8 x 1.6 x 1.2 cm)
Wt: 15.7 g
Mud Tank, Harte Range, Northern Territories, Australia
This thumbnail specimen consists of a single Zircon crystal that is not quite complete but is in excellent condition. Its doubly-terminated tetragonal prismatic form is a bit rough but still quite good, and it has the red-brown color that is common for its species. The crystal is dimly translucent due to intense internal fracturing and has a slightly dull adamantine luster. When bathed in longwave ultraviolet light, it glows a noticeable yellow.
no photo
zir-15 ($ 78.00)
Mud Tank, Harte Range, Northern Territories, Australia
ZIRCON specimen zir-16
$ 48.00
Dims:1.6x1.2x1.0" (4.1x3.0x2.5 cm)
Wt: 1.1oz. (31g)
Mt. St. Hilaire, Quebec, Canada
The matrix of this miniature is covered with brown zircon crystals. These crystals range in size from near-microscopic to 0.7" (1.8cm) in size. The larger crystals are completely opaque, but some of the tiny crystals are nearly transparent. One of the larger crystals is elongated on the c-axis. This is an excellent specimen from an outstanding locality. This piece is firmly glued to a clear acrylic base.
no photo
zir-16 ($ 48.00)
Mt. St. Hilaire, Quebec, Canada

 


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