Bytownite

Refractive Index: 1.5700
Abbe Number: 55.0
Crystal System: Isotropic (cubic)
Formation: Natural
Dispersion Data: Approximate (from n, V)
Fits: 1

Refraction Fits

Fit #1— Cauchy from (n_D, V_D estimated from plagioclase family)

Cauchy approximation

Valid 0.38–0.78 µm

$n$

n

= 1.5700

V_{D}

= 55.0

n (λ) = 1.5544 + 0.005425/ λ^{2}

Ca-rich plagioclase feldspar. Dispersion estimated from feldspars. n_D from published gemological tables; V_D estimated from plagioclase family because species-specific dispersion is not widely reported. Source: Winchell / GIA / Liddicoat compilations.

Absorption Specimens