Ulexite

Refractive Index: 1.5100
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)

Cauchy approximation

Valid 0.38–0.78 µm

$n$

n

= 1.5100

V_{D}

= 55.0

n (λ) = 1.496 + 0.004854/ λ^{2}

Hydrated Na-Ca borate; exhibits optical fiber-bundle effect. GIA dispersion 0.014. Source: GIA / Winchell / Liddicoat gemological tables.

Absorption Specimens

United States, California (Kern County), Boron