Materials
/
Beryllonite
Beryllonite
Refractive Index
1.5573–1.5580
Abbe Number
71.7–75.4
Crystal System
Isotropic (cubic)
Formation
Natural
Dispersion Data
Measured (published fit)
Fits
2
Refraction Fits
Fit #1
Shannon / Cauchy
n
n
=
1.5573
V
D
=
75.4
n
400
450
500
550
600
650
700
750
1.550
1.560
1.570
n
2
=
1
+
0.7187
(
λ
2
−
0.008209
)
λ
2
Fit #2
— Specimen fit
Shannon / Cauchy
n
n
=
1.5580
V
D
=
71.7
n
400
450
500
550
600
650
700
750
1.550
1.560
1.570
1.580
n
2
=
1
+
0.7185
(
λ
2
−
0.008629
)
λ
2
Stoneham, ME
Absorption Specimens
LED
SUN
I
F
Beryllonite
United States, Maine (Oxford County)
LED
SUN
I
F
Beryllonite
United States, Maine (Oxford County)
LED
SUN
I
F
Beryllonite
United States, Maine (Oxford County)
LED
SUN
I
F
Beryllonite
United States, Maine (Oxford County), Stoneham