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 |
Barberiite | 1.308 | B-+ | 90 | No | Calculated β index | |||
Avogadrite # | 1.3239 | 1.3245 | 1.3247 | B- | 75 | .0008 | No | |
Niter # | 1.332 | 1.504 | 1.504 | B- | 7 | .1720 | No | weak, r < v |
Cryolite # | 1.3385 to 1.339 | 1.3389 to 1.339 | 1.3396 to 1.34 | B+ | 43 | .0011 | Yes | none |
Sassolite # | 1.34 | 1.456 | 1.459 | B- | 5 | .1190 | Yes | none |
Nitromagnesite # | 1.34 | 1.506 | 1.506 | B- | 5 | .1660 | No | |
Weberite # | 1.346 | 1.348 | 1.35 | B+ | 83 | .0040 | No | |
Qilianshanite | 1.351 | 1.459 | 1.486 | B- | 50 | .1350 | No | |
Barentsite | 1.358 | 1.479 | 1.53 | B- | 62 | .1720 | No | r < v weak |
Simmonsite ! | 1.359 | 1.359 | 1.359 | B | 27 | .0000 | No | |
Neighborite | 1.364 | 1.367 | B | .0030 | No | |||
Glushinskite | 1.365 | 1.53 | 1.595 | B- | .2300 | No | ||
Nahcolite # | 1.377 | 1.503 | 1.583 | B- | 75 | .2060 | Yes | |
Kalicinite # | 1.38 | 1.482 | 1.578 | B- | 81.5 | .1980 | No | |
Darapskite # | 1.388 | 1.479 | 1.486 | B- | 27 | .0980 | No | |
Mirabilite # | 1.396 | 1.4103 | 1.419 | B- | 75.93 | .0230 | Yes | none |
Wheatleyite | 1.4 | 1.499 | 1.667 | B+ | 83 | .2670 | No | |
Natron # | 1.405 | 1.425 | 1.44 | B- | 71 | .0350 | Yes | r > v |
Thomsenolite # | 1.4072 | 1.4136 | 1.415 | B- | 50 | .0078 | No | |
Natrite | 1.41 | 1.535 | 1.543 | B- | 28 | .1330 | No | |
Pachnolite # | 1.411 | 1.413 | 1.42 | B+ | 76 | .0090 | No | |
Carlhintzeite | 1.411 | 1.416 | 1.422 | B+ | 77 | .0110 | No | |
Trona # | 1.412 | 1.492 | 1.54 | B- | 72 | .1280 | No | relatively strong |
Nesquehonite # | 1.412 | 1.501 | 1.526 | B- | 53 | .1140 | No | |
Yaroslavite | 1.413 | 1.416 to 1.417 | 1.423 | B- | 74 | .0100 | No | |
Natroxalate ! | 1.415 | 1.524 | 1.592 | B- | 72 | .1770 | No | |
Meridianiite ! | 1.418 | 1.448 | B | .0300 | No | |||
Thermonatrite # | 1.42 | 1.506 | 1.524 | B- | 48 | .1040 | No | |
Santite | 1.422 | 1.435 | 1.48 | B+ | .0580 | No | ||
Teschemacherite # | 1.4227 | 1.5358 | 1.5545 | B- | 41.633 | .1318 | No | |
Svyazhinite | 1.423 | 1.439 | 1.444 | B- | small | .0210 | No | |
Karasugite | 1.424 | 1.432 | 1.4415 | B+ | 94-94.5 | .0175 | No | |
Wilcoxite | 1.424 | 1.436 | 1.438 | B- | 48 | .0140 | No | not discernible |
Lindbergite ! | 1.424 | 1.55 | 1.65 | B- | 80 | .2260 | No | r > v very weak |
Calcjarlite | 1.425 | 1.428 | 1.432 | B+ | 72 | .0070 | No | |
Hexahydrite # | 1.426 | 1.453 | 1.456 | B- | 38 | .0300 | Yes | none |
Zabuyelite | 1.4285 | 1.5672 | 1.5743 | B- | 25 | .1458 | No | |
Jarlite # | 1.429 | 1.433 | 1.436 | B-+ | 90 | .0070 | No | |
Ameghinite | 1.429 | 1.528 | 1.538 | B- | 33 | .1090 | Yes | |
Kalinite # | 1.43 | 1.452 | 1.485 | B- | 52 | .0550 | Yes | none |
IMA2002-034 ! | 1.43 | 1.454 | 1.47 | B- | ~70 | .0400 | No | |
Matteuccite # | 1.43 | 1.46 | 1.48 | B- | 86 | .0500 | No | |
Sborgite # | 1.431 | 1.438 | 1.507 | B+ | 35 | .0760 | No | |
Deliensite ! | 1.432 | 1.47 | 1.492 | B- | 73 | .0600 | Yes | weak, r > v |
Bogvadite | 1.433 | 1.436 | 1.4389 | B- | 87 | .0059 | No | |
Epsomite # | 1.433 | 1.455 | 1.461 | B- | 52 | .0280 | Yes | none |
Wegscheiderite | 1.433 | 1.519 | 1.528 | B- | 32.4 | .0950 | No | |
Wattevilleite # | 1.435 | 1.455 | 1.459 | B- | 48 | .0240 | No | dispersion not observed |
Jorgensenite ! | 1.436 | 1.442 | 1.442 | B- | 0-5 | .0060 | No | |
Oxammite # | 1.438 | 1.547 | 1.595 | B- | 62 | .1570 | No | |
Kogarkoite | 1.439 | 1.439 | 1.442 | B+ | near 0 | .0030 | Yes | |
Stercorite # | 1.439 | 1.442 | 1.469 | B+ | 35.567 | .0300 | No | |
Lecontite # | 1.44 | 1.454 | 1.455 | B- | 29.74 | .0150 | No | |
Khademite | 1.44 | 1.46 | 1.487 | B- | 68 | .0470 | No | |
Usovite | 1.441 | 1.442 | 1.444 | B+ | 70 | .0030 | Yes | |
Admontite | 1.442 | 1.504 | B- | 30 | .0620 | Yes | ||
Catalanoite ! | 1.443 | 1.457 | 1.458 | B- | 29.6 | .0150 | Yes | r > v strong |
Gaylussite # | 1.444 | 1.5155 | 1.523 | B- | 34 | .0790 | No | relatively strong |
Mercallite # | 1.445 | 1.46 | 1.491 | B+ | 56 | .0460 | No | |
Hungchaoite | 1.445 | 1.485 | 1.49 | B- | 15 | .0450 | No | |
Thermessaite ! | 1.445 | B | No | Calculated | ||||
Borax # | 1.447 | 1.469 to 1.47 | 1.472 | B- | 39-40 | .0250 | Yes | r > v distinct |
Goslarite # | 1.447 to 1.463 | 1.475 to 1.48 | 1.47 to 1.485 | B- | 46 | .0230 | Yes | none |
Gearksutite # | 1.448 | 1.454 | 1.456 | B- | .0080 | No | ||
Burkeite # | 1.448 | 1.489 | 1.493 | B- | 34 | .0450 | Yes | r > v distinct |
Ferrosaponite ! | 1.448 | 1.641 | 1.642 | B- | 5 | .1940 | Yes | Calculated α index |
Chesnokovite ! | 1.449 | 1.453 | 1.458 | B+ | 80 | .0090 | No | |
Mendozite # | 1.449 | 1.461 | 1.463 | B- | 56 | .0140 | No | |
Acuminite | 1.4507 | 1.4528 | 1.4624 to 1.4627 | B+ | 46-57 | .0117 to .0120 | No | |
Kanemite | 1.451 | 1.47 | 1.478 | B- | 46 | .0270 | No | |
Tikhonenkovite | 1.452 | 1.456 | 1.458 | B- | 70 | .0060 | No | |
Stenonite | 1.452 | 1.527 | 1.538 | B- | 43 | .0860 | No | |
Kanonerovite ! | 1.453 | 1.459 | B- | Yes | 2V could not be measured | |||
Bayleyite # | 1.453 to 1.455 | 1.49 to 1.492 | 1.498 to 1.502 | B- | 30 | .0450 to .0470 | Yes | |
Dorfmanite | 1.454 | 1.461 | 1.471 | B+ | 65 | .0170 | No | very weak, r > v |
Kernite # | 1.454 | 1.472 | 1.488 | B- | 80 | .0340 | Yes | r > v distinct |
Zugshunstite-(Ce) ! | 1.455 | 1.485 | 1.528 | B+ | 85 | .0730 | Yes | medium, r > v |
Hellyerite # | 1.455 | 1.503 | 1.549 | B- | 85 | .0940 | No | |
Ikaite | 1.455 | 1.538 | 1.545 | B- | 45 | .0900 | No | distinct |
Chessexite | 1.456 | 1.46 | 1.48 | B+ | 47 | .0240 | No | |
Horvathite-(Y) ! | 1.457 | 1.543 | 1.622 | B- | 82 | .1650 | Yes | none |
Chvaleticeite | 1.457 | 1.506 | B | .0490 | No | |||
Barringtonite | 1.458 | 1.473 | 1.501 | B+ | 73.7 | .0430 | No | |
Gwihabaite ! | 1.458 | 1.527 | 1.599 | B- | 90 | .1410 | No | none |
Aluminite # | 1.459 | 1.464 | 1.47 | B+ | 90 | .0110 | Yes | none |
Cattiite ! | 1.459 | 1.47 | 1.47 | B- | 25 | .0110 | Yes | |
Jurbanite | 1.459 | 1.473 | 1.483 | B- | 80 | .0240 | No | |
Megacyclite | 1.46 | 1.478 | 1.481 | B- | 44 | .0210 | No | r > v strong |
Picromerite # | 1.4607 | 1.4629 | 1.4755 | B+ | 47.9 | .0148 | No | |
Rostite | 1.461 | 1.47 | 1.484 | B+ | .0230 | No | ||
Creedite # | 1.461 | 1.478 | 1.485 | B- | 64.37 | .0240 | No | |
Alpersite ! | 1.462 | 1.465 | 1.469 | B+ | 79.8 | .0070 | No | r > v weak |
Mallardite # | 1.462 | 1.465 | 1.474 | B+ | 80-90 | .0120 | No | |
Boggildite # | 1.462 | 1.466 | 1.469 | B+ | 78-80 | .0070 | No | |
Moraesite # | 1.462 | 1.482 | 1.49 | B- | 65 | .0280 | No | |
Aubertite | 1.462 | 1.482 | 1.495 | B- | 71 | .0330 | No | |
Konyaite | 1.464 | 1.468 | 1.474 | B+ | 74 | .0100 | No | |
Lansfordite # | 1.465 | 1.468 | 1.507 | B+ | 59.5 | .0420 | No | |
Sasaite | 1.465 | 1.473 | 1.477 | B- | 15 | .0120 | No | |
Baylissite | 1.465 | 1.485 | 1.535 | B- | 64 | .0700 | No |