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Biaxial Minerals sorted by Index of Refraction |
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Biaxial Minerals sorted by Index of Refraction |
( Bold - Valid Mineral Name)
(* - Mineral Name is Not IMA Approved)
(! - New Dana Classification Number Has Been Changed or Added)
(? - IMA Discredited Mineral Species Name)
(# - Grandfathered as valid)
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| Mineral Name | α | β | γ | Sign | 2V | Bire | Pleo- chroic |
Dispersion |
| Bergenite | 1.66 | 1.7 to 1.71 | 1.722 | B- | 60 | .0620 | Yes | |
| Tarbuttite # | 1.66 | 1.705 | 1.713 | B- | 50 | .0530 | Yes | strong |
| Zincolibethenite ! | 1.66 | 1.705 | 1.715 | B- | .0550 | Yes | r < v medium | |
| Urancalcarite | 1.66 | 1.712 | 1.736 | B- | 67 | .0760 | No | |
| Lavendulan # | 1.66 | 1.715 | 1.734 | B- | 33 | .0740 | No | |
| Tetraferriannite | 1.66 | 1.72 | 1.728 | B- | 40 | .0680 | Yes | |
| Hydroastrophyllite | 1.66 | 1.72 | 1.728 | B- | 40 | .0680 | Yes | |
| Calcioancylite-(Nd) | 1.66 | 1.725 | 1.761 | B- | 70-74 | .1010 | No | |
| Umohoite # | 1.66 | 1.831 | 1.915 | B- | 65 | .2550 | Yes | |
| Kornerupine # | 1.66 to 1.671 | 1.673 to 1.683 | 1.674 to 1.684 | B- | 3-48 | .0140 | Yes | r > v or r < v |
| Liskeardite # | 1.661 | 1.675 | 1.689 | B+ | 90 | .0280 | No | |
| Uranophane-beta # | 1.661 to 1.671 | 1.682 to 1.694 | 1.689 to 1.702 | B- | 0-71 | .0280 to .0310 | Yes | r > v strong |
| Clinohedrite # | 1.662 | 1.667 | 1.669 | B- | .0070 | No | ||
| Nacareniobsite-(Ce) | 1.662 | 1.671 | 1.692 | B+ | 66 | .0300 | No | |
| Bearthite | 1.662 | 1.671 | 1.696 | B+ | 65 | .0340 | No | |
| Allanpringite ! | 1.662 | 1.675 | 1.747 | B+ | .0850 | Yes | dispersion not observed | |
| Kainosite-(Y) # | 1.662 to 1.665 | 1.682 to 1.689 | 1.687 to 1.692 | B- | 40 | .0250 to .0270 | No | strong, r < v |
| Omphacite # | 1.662 to 1.701 | 1.67 to 1.712 | 1.685 to 1.723 | B+ | 58-83 | .0230 | Yes | r > v moderate |
| Olmiite ! | 1.663 | 1.672 | 1.694 | B+ | 71.8 | .0310 | Yes | r > v |
| 1.663 | 1.674 | 1.699 | B+ | .0360 | No | r > v strong | ||
| Aluminotaramite ! | 1.663 | 1.675 | 1.684 | B- | 71 | .0210 | Yes | r << v extreme |
| Ruizite | 1.663 | 1.715 | 1.734 | B- | 60 | .0710 | No | |
| Tengchongite | 1.663 | 1.76 | 1.762 | B- | 16 | .0990 | No | |
| Cascandite | 1.663 | 1.684 | B | .0210 | No | |||
| Grunerite # | 1.663 to 1.686 | 1.68 to 1.709 | 1.696 to 1.729 | B- | 90-70 | .0330 to .0430 | Yes | r > v |
| Diopside # | 1.663 to 1.699 | 1.671 to 1.705 | 1.693 to 1.728 | B+ | 58-63 | .0300 | Yes | weak to distinct, r > v |
| Arrojadite ! | 1.664 | 1.67 | 1.675 | B+ | 86 | .0110 | No | |
| Itoigawaite ! | 1.664 | 1.674 | 1.688 | B+ | 81 | .0240 | Yes | |
| Barahonaite-(Fe) ! | 1.664 | 1.677 | 1.677 | B- | 45-80 | .0130 | Yes | |
| Lakebogaite ! | 1.664 | 1.681 | 1.686 | B+ | 80-85 | .0220 | Yes | r > v strong |
| Guanacoite ! | 1.664 | 1.691 | 1.695 | B- | 31 | .0310 | No | |
| Ferristrunzite | 1.664 | 1.698 | 1.757 | B+ | 77 | .0930 | Yes | |
| Kankite | 1.664 | 1.68 | B | .0160 | No | |||
| Ruifrancoite ! | 1.665 | 1.665 | 1.682 | B+ | 0-10 | .0170 | Yes | r > v very strong |
| Rinkite ! | 1.665 | 1.668 | 1.681 | B+ | 43 | .0160 | No | strong, r < v |
| Lawsonite # | 1.665 | 1.672 to 1.676 | 1.684 to 1.686 | B+ | 84-85 | .0190 to .0210 | Yes | strong, r > v |
| Khibinskite | 1.665 | 1.715 | 1.715 | B- | 6-16 | .0500 | No | |
| Tsepinite-Ca ! | 1.666 | 1.676 | 1.78 | B+ | 30 | .1140 | Yes | r < v very weak |
| Clinotyrolite | 1.666 | 1.686 | 1.694 | B- | 65-66 | .0280 | No | |
| Calumetite | 1.666 | 1.69 | 1.69 | B | 2 | .0240 | No | |
| Erlianite | 1.667 | 1.674 | 1.679 | B- | 56-59 | .0120 | No | |
| Paratsepinite-Ba ! | 1.667 | 1.674 | 1.77 | B+ | 30 | .1030 | Yes | dispersion not observed |
| Leakeite | 1.667 | 1.675 | 1.691 | B- | 59-71 | .0240 | Yes | |
| Lemmleinite-K ! | 1.667 | 1.677 | 1.802 | B+ | 32 | .1350 | Yes | |
| Hubeite ! | 1.667 | 1.679 | 1.69 | B- | 89 | .0230 | Yes | |
| Sinhalite # | 1.667 to 1.676 | 1.697 to 1.704 | 1.705 to 1.712 | B- | 55 | .0380 | Yes | |
| Gjerdingenite-Fe ! | 1.6676 | 1.7001 | 1.794 | B+ | 58.5 | .1264 | Yes | dispersion not observed |
| Fluorarrojadite-(BaFe) ! | 1.668 | 1.67 | 1.682 | B+ | 37 | .0140 | Yes | dispersion not observed |
| Magnesioriebeckite # | 1.668 | 1.672 | 1.68 | B- | 75-85 | .0120 | No | |
| Bykovaite ! | 1.668 | 1.679 | 1.71 | B+ | 63 | .0420 | Yes | |
| Walstromite | 1.668 | 1.684 | 1.685 | B- | 30 | .0170 | Yes | weak |
| Ferro-actinolite # | 1.668 | 1.685 | 1.702 | B- | 10-12 | .0340 | No | |
| Magnesiochlorophoenicite # | 1.669 | 1.672 | 1.677 | B+ | .0080 | No | ||
| Lithiophilite # | 1.669 | 1.673 | 1.682 | B+ | 65 | .0130 | No | |
| Goedkenite | 1.669 | 1.673 | 1.692 | B+ | 45-50 | .0230 | No | |
| Avdoninite ! | 1.669 | 1.688 | 1.707 | B-+ | .0380 | Yes | dispersion not observed | |
| Yingjiangite | 1.669 | 1.692 | 1.71 | B- | 83 | .0410 | Yes | |
| Boltwoodite # | 1.669 | 1.6955 | 1.7005 | B- | .0315 | Yes | ||
| Prismatine ! | 1.669 to 1.671 | 1.681 to 1.83 | 1.682 to 1.684 | B- | 28-38 | .0130 | No | |
| Potassic-chlorohastingsite ! | 1.669 to 1.68 | 1.682 to 1.695 | 1.684 to 1.705 | B- | .0150 to .0250 | No | ||
| Hastingsite # | 1.669 to 1.68 | 1.682 to 1.695 | 1.684 to 1.705 | B- | 40-81 | .0150 to .0250 | Yes | r > v distinct |
| 1.669 to 1.755 | 1.674 to 1.763 | 1.68 to 1.773 | B- | 70-90 | .0110 to .0180 | Yes | weak, r < v | |
| Katayamalite | 1.67 | 1.671 | 1.677 | B+ | 32 | .0070 | No | r > v strong |
| Metavanmeersscheite | 1.67 | 1.68 | 1.69 | B- | 83 | .0200 | No | |
| Gjerdingenite-Mn ! | 1.67 | 1.685 | 1.775 | B+ | 52 | .1050 | No | r < v weak |
| Lavenite # | 1.67 | 1.69 | 1.72 | B- | 40-70 | .0500 | Yes | r < v perceptible |
| Parakeldyshite | 1.67 | 1.692 | 1.713 | B- | 84-88 | .0430 | Yes | |
| Sussexite # | 1.67 | 1.728 | 1.732 | B- | 25 | .0620 | No | |
| Lomonosovite # | 1.67 | 1.75 | 1.778 | B- | 56 | .1080 | Yes | |
| Nullaginite | 1.67 | 1.78 | 1.78 | B | .1100 | No | ||
| Keldyshite | 1.67 | 1.71 | B | 60 | .0400 | No | ||
| Clinozoisite-(Sr) ! | 1.67 | 1.725 | B | .0550 | Yes | |||
| Sarcopside # | 1.67 to 1.676 | 1.728 to 1.73 | 1.73 to 1.734 | B- | 26-28 | .0600 | No | r > v perceptible |
| Kaersutite # | 1.67 to 1.689 | 1.69 to 1.741 | 1.7 to 1.772 | B- | 66-82 | .0300 to .0830 | No | |
| Pumpellyite-(Mg) # | 1.67 to 1.698 | 1.672 to 1.706 | 1.684 to 1.72 | B+ | 10-50 | .0140 to .0220 | Yes | relatively strong |
| 1.67 to 1.73 | 1.7 to 1.76 | 1.72 to 1.77 | B- | .0500 | No | relatively strong | ||
| Natrophilite # | 1.671 | 1.674 | 1.684 | B+ | 75 | .0130 | No | relatively strong |
| Gedrite # | 1.671 | 1.681 | 1.69 | B- | 75 | .0190 | No | |
| Bussenite ! | 1.671 | 1.694 | 1.734 | B+ | 71 | .0630 | Yes | strong, r > v |
| Baratovite | 1.672 | 1.672 | 1.673 | B+ | 60 | .0010 | No | r > v strong |
| Akrochordite # | 1.672 | 1.676 | 1.683 | B | .0110 | No | ||
| Mapimite | 1.672 | 1.678 | 1.712 | B+ | 50 | .0400 | No | |
| Potassicleakeite ! | 1.672 | 1.68 | 1.692 | B+ | .0200 | Yes | ||
| Phosphoferrite # | 1.672 | 1.68 | 1.7 | B+ | 68 | .0280 | No | r > v distinct |
| Talmessite | 1.672 | 1.685 | 1.698 | B- | 90 | .0260 | No | |
| Jagowerite | 1.672 | 1.693 | 1.71 | B+ | 80 | .0380 | Yes | |
| Urusovite ! | 1.672 | 1.718 | 1.722 | B- | ~30 | .0500 | Yes | |
| Lintisite | 1.672 | 1.739 | 1.802 | B- | 85 | .1300 | No | |
| Rosasite # | 1.672 | 1.829 | 1.83 | B- | 0-5 | .1580 | No | |
| Axinite-(Mn) # | 1.672 to 1.693 | 1.677 to 1.701 | 1.681 to 1.704 | B- | 69-87 | .0090 to .0110 | Yes | strong, r < v |
| Axinite-(Fe) # | 1.672 to 1.693 | 1.677 to 1.701 | 1.681 to 1.704 | B- | 69-87 | .0090 to .0110 | Yes | strong, r < v |
| Axinite-(Mg) | 1.672 to 1.693 | 1.677 to 1.701 | 1.681 to 1.704 | B- | 69-87 | .0090 to .0110 | Yes | strong, r < v |
| Sadanagaite | 1.673 | 1.684 | 1.697 | B- | 80-90 | .0240 | Yes | |
| Chukanovite ! | 1.673 | 1.77 | 1.78 | B- | 10 | .1070 | No | |
| Samfowlerite | 1.674 | 1.68 | 1.681 | B- | 29 | .0070 | No | |
| Magnesiosadanagaite ! | 1.674 | 1.683 | 1.694 | B+ | 80-90 | .0200 | Yes | Calculated β index |
| Potassic-magnesiosadanagaite | 1.674 | 1.686 | 1.699 | B- | 90 | .0250 | Yes | |
| Ianthinite # | 1.674 | 1.9 | 1.92 | B- | 58 | .2460 | Yes | |
| Kirschsteinite # | 1.674 to 1.693 | 1.694 to 1.734 | 1.706 to 1.735 | B- | 50 | .0320 to .0420 | Yes | |
| Strelkinite | 1.674 to 1.77 | 1.855 to 1.907 | 1.88 to 1.915 | B- | medium | .2060 | Yes |