Orthoclase

Refractive Index: 1.5220
Abbe Number: 60.0
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

= 1.5220

V_{D}

= 60.0

n (λ) = 1.5089 + 0.004554/ λ^{2}

K-feldspar; parent of moonstone. GIA dispersion 0.012. Source: GIA / Winchell / Liddicoat gemological tables.

Absorption Specimens

Madagascar, Toliara Province (Betroka District), Itrongahy

Madagascar, Toliara Province (Betroka District), Itrongahy

Myanmar, Mandalay Division, Mogok (Kathé)

Sri Lanka, Sabaragamuwa Province, Eheliyagoda

United States, Oregon (Lake County), Plush