Datolite

Refractive Index: 1.6484–1.6487
Abbe Number: 65.0–67.3
Crystal System: Isotropic (cubic)
Formation: Natural
Dispersion Data: Measured (published fit)
Fits: 2

Refraction Fits

Fit #1

Shannon / Cauchy

$n$

n

= 1.6484

V_{D}

= 65.0

n^{2} = 1 + \frac{λ ^{2}}{0.599 ( λ ^{2} - 0.009683 )}

Fit #2— Specimen fit

Shannon / Cauchy

$n$

n

= 1.6487

V_{D}

= 67.3

n^{2} = 1 + \frac{λ ^{2}}{0.5981 ( λ ^{2} - 0.009363 )}

Westfield, MA

Absorption Specimens

United States, Massachusetts (Hampden County), Westfield (Lane Quarry)