Topaz

Refractive Index: 1.6149–1.6327
Abbe Number: 77.8–104.9
Crystal System: Isotropic (cubic)
Formation: Natural
Dispersion Data: Measured (published fit)
Fits: 5

Refraction Fits

Fit #1

Shannon / Cauchy

$n$

n

= 1.6193

V_{D}

= 77.8

n^{2} = 1 + \frac{λ ^{2}}{0.6312 ( λ ^{2} - 0.00808 )}

Fit #2— Specimen fit

Shannon / Cauchy

$n$

n

= 1.6327

V_{D}

= 104.9

n^{2} = 1 + \frac{λ ^{2}}{0.611 ( λ ^{2} - 0.006056 )}

Fit #3— Specimen fit

Shannon / Cauchy

$n$

n

= 1.6161

V_{D}

= 81.5

n^{2} = 1 + \frac{λ ^{2}}{0.6346 ( λ ^{2} - 0.007721 )}

Fit #4— Specimen fit

Shannon / Cauchy

$n$

n

= 1.6154

V_{D}

= 79.9

n^{2} = 1 + \frac{λ ^{2}}{0.6357 ( λ ^{2} - 0.007865 )}

Fit #5— Specimen fit

Shannon / Cauchy

$n$

n

= 1.6149

V_{D}

= 80.0

n^{2} = 1 + \frac{λ ^{2}}{0.6363 ( λ ^{2} - 0.007858 )}

Absorption Specimens

Brazil, Minas Gerais State, Ouro Preto

Brazil, Minas Gerais State, Ouro Preto

Brazil, Minas Gerais State, Ouro Preto

Brazil, Minas Gerais State, Ouro Preto

Brazil, Minas Gerais State, Ouro Preto

Brazil, Minas Gerais State, Ouro Preto

Brazil, Minas Gerais State, Ouro Preto (Dom Bosco Mine)

Brazil, Minas Gerais State, Ouro Preto (Dom Bosco Mine)

Pakistan, North-West Frontier Province, Mardan (Katlang Mine)

Russia, Chelyabinsk Province, Sanarka River

Sri Lanka, Sabaragamuwa Province, Ratnapura

Sri Lanka, Sabaragamuwa Province, Ratnapura

Zimbabwe, Mashonaland West Province (Karoi District), Mwami (St. Anne's Mine)

Zimbabwe, Mashonaland West Province (Karoi District), Mwami (St. Anne's Mine)