Zircon

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: Blue Zircon Gemstone

: Colorless Zircon Gemstone

: Brown Zircon Rough

: Golden Brown zircon Rough

: Orange Red Zircon Gemstone

: Pink Zircon Gemstone

Refractive Index : 1,984 – 1.925 (+ 0.040 – 0.145)

Optical Characteristic : DR, Uniaxial positive

Specific Gravity : 4.70 (+ 0.03 – 0.80)

Formula : ZrSiO4 +Fe,U,Th,Hf

Crystal System : Tetragonal

Variety/Species : Zircon is classified as high, medium or low type (also called as alpha, beta or gamma type), depending on the extent of structural breakdown. But in trade practice, it is sufficient to identify the stone simply as zircon and specify it according to color.High and Medium – Transparent colorless, blue, yellow to yellow green, brownish green, orange to brown, brownish to orangy red.Low (Metamict) – Transparent brownish to yellowish green with a cloudy texture, more rarely brown or orange.

Hyacinth or Jacinth – Transparent reddish-brown .This term was also applied to hessonite garnet

Jargoon or Jargon – Light yellow to colorless stones from Sri Lanka (Ceylon)

Beccarite – Green

Melichrysos – Yellow

Sparklite – Colorless

Starlite and Stremlite – Blue

Species/Group : Zircon

Birefringence : 0.0 to 0.059

Dispersion : 0.038

Hardness : 6 to 7.5

Toughness : Poor to good

Ultrasonic : Risky

Steam : Risky

UV Long :
Blue – Inert to moderate light blue (LW)Green – Generally Inert

Yellow to Orange Yellow – Inert to moderate yellow to orange (SW to LW)

Red to orange-red – Inert to strong yellow to orange (SW)
Brown – Inert to very weak red (SW)

UV Short : See Above

Pleochroism : 2 colors

Strength : weak

Pleochroism Colors : Blue – Strong blue and brownish yellow to colorlessGreen – Very weak green and yellow green

Orange and brown – weak to moderate purplish brown and brownish yellow

Red – Moderate reddish purple and purplish brown

Heat : May change color

Acids : No reaction

Light : Usually safe

Polish Luster : Vitreous to subadamantine

Fracture : Conchoidal

Fracture Luster : Vitreous to subadamantine

Clarity Type : I to II

Tones : 2-8

Saturations : 1-4

Cause of Color : Color centers

Enhancements : HeatingEffect – Changes color from brown to red, orange, yellow, colorless or blue. Almost all colorless zircons in the market have been heat treated and this treatment is quite stable cannot be detected.

Some stones though revert back to its original color when exposed to sunlight.

Cleavage : Imperfect

Color Range : See Varieties

Transparency : Transparent

Phenomena : Chatoyancy,(rare)

Separations : Zircon from-
Spessartite Garnet : optic character, magnification, spectrum

Andradite Garnet : optic character, magnification, spectrum(possibly)

CZ : doubling, spectrum, SG, magnification, dispersion

YAG : doubling, spectrum, magnification

Sphene : SG, spectrum, optic character

Sphalerite : optic character, magnification, cleavage, diapersion, spectrum(possibly)

Synthetic rutile : doubling (comparative), dispersion, magnification, spectrum, SG (possibly)

GGG : Doubling, spectrum, SG, magnification

Diamond : Doubling, spectrum, SG, magnification, thermal tester

Strontium titanate : Doubling, dispersion, spectrum, SG, magnification

Identifying Characteristics and information
Tiny, white fluffy inclusions, strong twinning or zoning, angular inclusions.Wide variance in SG-4.70 to 3.90. Most gem zircon has high-end properties, often has abraded facet junctions.

High zircon usually 7.5 in hardness;low type around 6. Almost always heat-treated; may fade.

Blue-white phosphorescence

Spectral Data
Strongest line:6535 .Also,6590,6910,6830,6625,6605,6210 many more

Trade Names and Misnomers
Alpha Zircon
Beccartite
Beta Zircon
Ceylon Diamond(M)
Cyrtolite
Gamma Zircon

Tags: Alpha Zircon, Beccarite, Beccartite, Beta Zircon, blue zircon, ceylon diamond, colorless zircon, Cyrtolite, Gamma Zircon, high zircon, Hyacinth, Jacinth, Jargon, Jargoon, low zircon, matara diamond, medium zircon, Melichrysos, siam aquamarine, Sparklite, Starlite, Stremlite, zircon