Fit #1— Cauchy from (n_D, V_D estimated from oxide family)
Cauchy approximation
Valid 0.38–0.78 µm
n
n = 1.7400VD = 50.0
n(λ)=1.7177+0.007747/λ2
MgO; optical material. Dispersion estimated. n_D from published gemological tables; V_D estimated from oxide family because species-specific dispersion is not widely reported. Source: Winchell / GIA / Liddicoat compilations.