Corundum

Ruby

Refractive Index: 1.7640
Abbe Number: 72.0
Crystal System: Isotropic (cubic)
Formation: Natural
Dispersion Data: Approximate (from n, V)
Fits: 1

Refraction Fits

Fit #1— Cauchy from (n_D, V_D)

Cauchy approximation

Valid 0.38–0.78 µm

$n$

n

= 1.7640

V_{D}

= 72.0

n (λ) = 1.748 + 0.005555/ λ^{2}

Cr-colored corundum. Refractive behavior identical to sapphire; the Malitson-Dodge Sellmeier for corundum-sapphire applies. Source: GIA / Winchell / Liddicoat gemological tables.

Absorption Specimens

Myanmar, Mandalay Division, Mogok

Nepal, Western Region (Gandaki Zone), Ganesh Himal