Andradite

Demantoid

Refractive Index: 1.8855–1.8863
Abbe Number: 22.8–23.9
Crystal System: Isotropic (cubic)
Formation: Natural
Dispersion Data: Measured (published fit)
Fits: 2

Refraction Fits

Fit #1

Shannon / Cauchy

$n$

n

= 1.8863

V_{D}

= 23.9

n^{2} = 1 + \frac{λ ^{2}}{0.4226 ( λ ^{2} - 0.026029 )}

Fit #2— Specimen fit

Shannon / Cauchy

$n$

n

= 1.8855

V_{D}

= 22.8

n^{2} = 1 + \frac{λ ^{2}}{0.4245 ( λ ^{2} - 0.027091 )}

Absorption Specimens

Iran, Kerman Province, Kerman

Italy, Lombardy, Malenco Valley