Birefringence

 

Birefringence is the difference between the high and low Refractive Index (RI) values of a gemstone. Careful rotation of the gemstone and repeated readings on a refractometer will usually provide the maximum spread between the refractive indices which is equal to the Birefringence of the gemstone. Birefringence values are often useful in quickly narrowing possible choices during gemstone indentification work. The first list below is in alphabetical order. The second list is in numerical order of birefrigence from highest to lowest. Click here to view the numerical list.

 

 

Gems (in alphabetical order)

birefrigence

Actinolite
Adventurine (Quartz)
Agate
Air (as a reference)
Albite (Feldspar)
Alexandrite
Allanite
Almandine (Garnet)
Amazonite (Feldspar)
Amber
Amblygonite
Amethyst
Ametrine
Anatase
Andalusite
Andesine (Feldspar)
Andradite (Garnet)
Angelsite
Anhydrite
Anorthite (Feldspar)
Apatite
Apophyllite
Aquamarine (Beryl)
Aragonite
Augelite
Axinite
Azurite
Barite
Benitoite
Beryl Family
Beryllonite
Bixbite (Beryl)
Boleite
Boracite
Brazilianite
Bronzite
Brookite
Brucite
Bustamite
Bytownite (Feldspar)
Calcite
Cancrinite
Carnelian
Cassiterite
Catapleiite
Celestite
Cerussite
Chalcedony
Chambersite
Charoite
Childrenite
Chrome Diopside
Chrysoberyl
Chrysocolla
Chrysoprase
Citrine
Clinohumite
Clinozoisite
Colemanite
Coral
Creedite
Crocoite
Cubic Zirconia
Cuprite
Danburite
Datolite
Demantoid (Garnet)
Diamond
Diaspore
Diopside
Dioptase
Dolomite
Dumortierite
Ekanite
Emerald (Beryl)
Emerald (synth. flux)
Emerald (synth. hydro)
Enstatite
Eosphorite
Epidote
Euclase
Eudialyte
Fayalite (Olivine)
Fluorite
Friedelite
Gahnite
Gahnospinel
Glass (man-made)
Goshenite (Beryl)
Grossular (Garnet)
Hackmanite
Hambergite
Hauyne
Heliodor (Beryl)
Hematite
Hemimorphite
Herderite
Hessonite (Garnet)
Hiddenite (Spodumene)
Howlite
Hydrogrossular (Garnet)
Hypersthene
Idocrase
Iolite
Jadeite (Jade)
Jasper (Quartz)
Jeremejevite
Kornerupine
Kunzite (Spodumene)
Kyanite
Labradorite (Feldspar)
Lapis Lazuli (Lazurite)
Lazulite
Legrandite
Leucite
Magnesite
Malachite
Manganotantalite
Microline (Feldspar)
Microlite
Moissanite
Moldavite
Monazite
Montebrasite
Moonstone (Feldspar)
Morganite (Beryl)
Nambulite
Natrolite
Nepheline
Nephrite (Jade)
Neptunite
Obsidian
Oligoclase (Feldspar)
Onyx
Opal
Orthoclase (Feldspar)
Painite
Parisite
Pearl
Pectolite
Periclase
Peridot (Olivine)
Peristerite (Feldspar)
Petalite
Phenakite
Phosgenite
Phosphophyllite
Poudretteite
Powellite
Prasiolite (Quartz)
Prehnite
Proustite
Purpurite
Pyrope (Garnet)
Pyroxmangite
Quartz (all colors)
Rhodizite
Rhodochrosite
Rhodolite (Garnet)
Rhodonite
Ruby (Corundum)
Rutile
Sanidine (Feldspar)
Sapphire (Corundum)
Sapphirine
Scapolite
Scheelite
Sellaite
Serandite
Serpentine
Shattuckite
Shortite
Siderite
Sillimanite
Simpsonite
Sinhalite
Smithsonite
Sodalite
Spessartite (Garnet)
Sphalerite
Sphene
Spinel
Spinel (synthetic)
Spodumene
Staurolite
Strontium Titanate
Sugilite
Sunstone (Feldspar)
Taaffeite
Tantalite
Tanzanite (Zoisite)
Tektite
Thaumasite
Thomsonite
Thulite (Zoisite)
Tiger eye (Quartz)
Topaz
Tourmaline (all colors)
Tremolite
Triphylite
Tsavorite (Garnet)
Tugtupite
Turquoise
Ulexite
Uvarovite (Garnet)
Vanadinite
Variscite
Vesuvianite
Villiamumite
Vivianite
Water
Weloganite
Whewellite
Willemite
Witherite
Wulfenite
Yugawaralite
Zektzerite
Zincite
Zircon, High
Zircon, Medium
Zircon, Low
Zoisite
  

0.022 - 0.026
0.009
0.004
0.000
0.011
0.009 - 0.010
0.013 - 0.036
0.000 (iso)
0.008 - 0.010
0.000
0.020 - 0.021
0.009
0.009
0.046 - 0.067
0.007 - 0.011
0.008
0.000 (iso)
0.017
0.044
0.013
0.001 - 0.013
0.001 or less
0.005 - 0.007
0.155
0.014 - 0.020
0.010 - 0.012
0.110
0.012
0.047
0.004 - 0.009
0.009
0.004 - 0.008
0.020
0.024
0.019 - 0.021
0.015
0.122 - 0.157
0.010 - 0.020
0.014 - 0.015
0.009
0.172 - 0.190
0.022
0.004
0.098
0.280
0.009 - 0.012
0.274
0.004
0.012
0.009
0.030 - 0.040
0.028
0.008 - 0.012
0.023 - 0.040
0.004
0.009
0.028 - 0.041
0.005 - 0.015
0.028
0.160
0.024
0.270
0.000 (iso)
0.000 (iso)
0.006 - 0.008
0.044 - 0.047
0.000 (iso)
0.000 (iso)
0.048
0.024 - 0.031
0.053
0.179 - 0.185
0.150 - 0.370
0.001
0.004 - 0.009
0.003 - 0.005
0.003 - 0.008
0.010
0.029 - 0.035
0.015 - 0.049
0.019 - 0.025
0.003 - 0.010
0.052
0.000 (iso)
0.030
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.004 - 0.008
0.000 (iso)
0.000 (iso)
0.072
0.000 (iso)
0.005 - 0.009
0.280
0.022
0.029 - 0.030
0.000 (iso)
0.014 - 0.027
0.022
0.000 (iso)
0.017
0.003 - 0.018
0.005 - 0.018
0.012 - 0.020
0.000
0.007 - 0.013
0.013 - 0.017
0.014 - 0.027
0.017
0.012
0.000 (iso)
0.031 - 0.036
0.060
0.000 (iso)
0.022
0.254
0.150
0.008 - 0.010
0.000
0.043
0.000 (iso)
0.049 - 0.055
0.021 - 0.022
0.005 - 0.008
0.008 - 0.009
0.023
0.012
0.004
0.027
0.029 - 0.045
0.000 (iso)
0.007
0.004
0.000 (iso)
0.005 - 0.008
0.027 - 0.028
0.081
0.155
0.036
0.000 (iso)
0.033 - 0.038
0.011
0.012 - 0.014
0.016
0.028
0.021 - 0.033
0.016 - 0.021
0.011
0.009
0.021 - 0.033
0.296
0.007
0.000 (iso)
0.016 - 0.020
0.009
0.000 (iso)
0.201 - 0.220
0.000 (iso)
0.011 - 0.014
0.008 - 0.009
0.287
0.005 - 0.008
0.008 - 0.009
0.006
0.015 - 0.026
0.016
0.012
0.028
0.014
0.063
0.039
0.240
0.020
0.058
0.035 - 0.037
0.227
0.000 (iso)1
0.000 (iso)
0.000 (iso)
0.100 - 0.192
0.000 (iso)
0.000 (iso)
0.014 - 0.027
0.011 - 0.015
0.000 (iso)
0.003 - 0.005
0.012
0.004 - 0.009
0.160
0.009
0.000 (iso)
0.036
0.021
0.006
0.009
0.008 - 0.011
0.020
0.017 - 0.027
0.006 - 0.008
0.000 (iso)
0.006 - 0.008
0.040
0.023
0.000 (iso)
0.066
0.031
0.003 - 0.018
0.000 (iso)
0.040 - 0.059
0.000
0.090
0.159 - 0.163
0.028
0.148
0.122
0.009
0.002
0.016
0.000 - 0.008
0.008 - 0.043
0.036 - 0.059
0.004 - 0.008
 

Numerical Birefingence List

0.296
0.287
0.280
0.280
0.274
0.270
0.254
0.240
0.227
0.201 - 0.220
0.179 - 0.185
0.172 - 0.190
0.160
0.160
0.159 - 0.163
0.155
0.155
0.150 - 0.370
0.150
0.148
0.122 - 0.157
0.122
0.110
0.100 - 0.192
0.098
0.090
0.081
0.072
0.066
0.063
0.060
0.058
0.053
0.052
0.049 - 0.055
0.048
0.047
0.046 - 0.067
0.044 - 0.047
0.044
0.043
0.040 - 0.059
0.040
0.039
0.036 - 0.059
0.036
0.036
0.035 - 0.037
0.033 - 0.038
0.031 - 0.036
0.031
0.030 - 0.040
0.030
0.029 - 0.045
0.029 - 0.035
0.029 - 0.030
0.029
0.028 - 0.041
0.028
0.028
0.028
0.028
0.028
0.027 - 0.028
0.027
0.024 - 0.031
0.024
0.024
0.023 - 0.040
0.023
0.023
0.022 - 0.026
0.022
0.022
0.022
0.022
0.021 - 0.033
0.021 - 0.033
0.021 - 0.022
0.021
0.020 - 0.021
0.020
0.020
0.020
0.019 - 0.025
0.019 - 0.021
0.017 - 0.027
0.017
0.017
0.017
0.016 - 0.021
0.016 - 0.020
0.016
0.016
0.016
0.015 - 0.049
0.015 - 0.026
0.015
0.014 - 0.027
0.014 - 0.027
0.014 - 0.027
0.014 - 0.020
0.014 - 0.015
0.014
0.013 - 0.036
0.013 - 0.017
0.013
0.012 - 0.020
0.012 - 0.014
0.012
0.012
0.012
0.012
0.012
0.012
0.011 - 0.015
0.011 - 0.014
0.011
0.011
0.011
0.010 - 0.020
0.010 - 0.012
0.010
0.009 - 0.012
0.009 - 0.010
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.009
0.008 - 0.043
0.008 - 0.012
0.008 - 0.011
0.008 - 0.010
0.008 - 0.010
0.008 - 0.009
0.008 - 0.009
0.008 - 0.009
0.008
0.007 - 0.013
0.007 - 0.011
0.007
0.007
0.006 - 0.008
0.006 - 0.008
0.006 - 0.008
0.006
0.006
0.005 - 0.018
0.005 - 0.015
0.005 - 0.009
0.005 - 0.008
0.005 - 0.008
0.005 - 0.008
0.005 - 0.007
0.004 - 0.009
0.004 - 0.009
0.004 - 0.009
0.004 - 0.008
0.004 - 0.008
0.004 - 0.008
0.004
0.004
0.004
0.004
0.004
0.004
0.003 - 0.018
0.003 - 0.018
0.003 - 0.010
0.003 - 0.008
0.003 - 0.005
0.003 - 0.005
0.002
0.001 - 0.013
0.001
0.001 or less
0.000 - 0.008
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000 (iso)
0.000
0.000
0.000
0.000
0.000
 

Proustite
Rutile
Catapleiite
Hematite
Cerussite
Crocoite
Malachite
Siderite
Smithsonite
Rhodochrosite
Dolomite
Calcite
Coral
Tantalite
Whewellite
Aragonite
Pearl
Dumortierite
Manganotantalite
Witherite
Brookite
Wulfenite
Azurite
Sphene
Cassiterite
Weloganite
Parisite
Hambergite
Vanadinite
Shattuckite
Legrandite
Simpsonite
Dioptase
Fayalite (Olivine)
Monazite
Diaspore
Benitoite
Anatase
Datolite
Anhydrite
Moissanite
Vivianite
Turquoise
Shortite
Zircon, Low
Pectolite
Thaumasite
Sinhalite
Peridot (Olivine)
Lazulite
Variscite
Childrenite
Friedelite
Neptunite
Eosphorite
Herderite
Painite
Clinohumite
Chrome Diopside
Colemanite
Phosgenite
Serandite
Willemite
Painite
Nephrite (Jade)
Diopside
Boracite
Creedite
Chrysocolla
Nambulite
Ulexite
Actinolite
Cancrinite
Hemimorphite
Howlite
Magnesite
Phosphophyllite
Prehnite
Montebrasite
Thomsonite
Amblygonite
Boleite
Sillimanite
Tourmaline (all colors)
Euclase
Brazilianite
Tremolite
Angelsite
Hypersthene
Kyanite
Poudretteite
Pyroxmangite
Phenakite
Scheelite
Zincite
Epidote
Scapolite
Bronzite
Hiddenite (Spodumene)
Kunzite (Spodumene)
Spodumene
Augelite
Bustamite
Serpentine
Allanite
Kornerupine
Anorthite (Feldspar)
Jadeite (Jade)
Petalite
Barite
Chambersite
Labradorite (Feldspar)
Natrolite
Sellaite
Sunstone (Feldspar)
Staurolite
Rhodonite
Albite (Feldspar)
Peristerite (Feldspar)
Powellite
Brucite
Axinite
Enstatite
Celestite
Alexandrite
Adventurine (Quartz)
Amethyst
Ametrine
Beryllonite
Bytownite (Feldspar)
Charoite
Citrine
Prasiolite (Quartz)
Quartz (all colors)
Tanzanite (Zoisite)
Tiger eye (Quartz)
Yugawaralite
Zircon, Medium
Chrysoberyl
Topaz
Amazonite (Feldspar)
Microline (Feldspar)
Morganite (Beryl)
Ruby (Corundum)
Sapphire (Corundum)
Andesine (Feldspar)
Jeremejevite
Andalusite
Oligoclase (Feldspar)
Purpurite
Danburite
Triphylite
Tugtupite
Sapphirine
Thulite (Zoisite)
Iolite
Clinozoisite
Heliodor (Beryl)
Moonstone (Feldspar)
Orthoclase (Feldspar)
Sanidine (Feldspar)
Aquamarine (Beryl)
Beryl Family
Emerald (Beryl)
Taaffeite
Bixbite (Beryl)
Goshenite (Beryl)
Zoisite
Agate
Carnelian
Chalcedony
Chrysoprase
Nepheline
Onyx
Idocrase
Vesuvianite
Eudialyte
Emerald (synth. hydro)
Sugilite
Emerald (synth. flux)
Zektzerite
Apatite
Ekanite
Apophyllite
Zircon, High
Almandine (Garnet)
Andradite (Garnet)
Cubic Zirconia
Cuprite
Demantoid (Garnet)
Diamond
Fluorite
Gahnite
Gahnospinel
Glass (man-made)
Grossular (Garnet)
Hackmanite
Hauyne
Hessonite (Garnet)
Hydrogrossular (Garnet)
Lapis Lazuli (Lazurite)
Leucite
Moldavite
Obsidian
Opal
Periclase
Pyrope (Garnet)
Rhodizite
Rhodolite (Garnet)
Sodalite
Spessartite (Garnet)
Sphalerite
Spinel
Spinel (synthetic)
Strontium Titanate
Tektite
Tsavorite (Garnet)
Uvarovite (Garnet)
Villiamumite
Air (as a reference)
Amber
Jasper (Quartz)
Microlite
Water
 

Notes:
Values may be approximate or may vary by mineral origin and associations with other minerals, or by color or inclusions, and by cleanliness and quality of gemstone polish.

(iso) refers to isotropic, meaning that light travels at the same speed in all directions within the gem. These gems have an isometric crystal structure or may be amorphous.

Reference: Color Encyclopedia of Gemstones, Second Edition (1987), by Joel E. Arem.

 


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