Monazite

Refractive Index: 1.8000
Abbe Number: 25.0
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

= 1.8000

V_{D}

= 25.0

n (λ) = 1.7518 + 0.016751/ λ^{2}

Rare-earth phosphate; very high dispersion. GIA dispersion 0.048. Source: GIA / Winchell / Liddicoat gemological tables.

Absorption Specimens

Brazil, Minas Gerais State