Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:
5-6 - Between Apatite and Orthoclase
Luster:
Sub Metallic
Streak:
light brown
Optical Properties of Jeppeite
Gladstone-Dale:
CI meas= 0.049 (Good) - where the CI = (1-KPDmeas/KC) CI calc= 0.057 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.3098,KPDmeas= 0.3122,KC= 0.3284 Ncalc = 2.29 - 2.3
Optical Data:
Biaxial (?), a=2.13, b=2.21, g=2.35, bire=0.2200
Pleochroism (x):
capri blue.
Pleochroism (y):
dark greenish brown.
Pleochroism (z):
dark olive buff.
RL Bireflectance:
Weak.
RL Color:
Gray, may have golden internal reflections.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Jeppeite in Air
λ
R1
R2
∑ R1(λ)
∑ R2(λ)
400 nm
16.10
19.50
420 nm
15.50
18.90
440 nm
15.00
18.40
460 nm
14.50
18.00
480 nm
14.20
17.60
500 nm
13.90
17.30
520 nm
13.60
17.00
540 nm
13.40
16.80
560 nm
13.20
16.60
580 nm
13.10
16.50
600 nm
13.00
16.40
620 nm
12.90
16.20
640 nm
12.90
16.20
660 nm
12.90
16.10
680 nm
12.80
16.00
700 nm
12.80
16.00
Calculated Relative Intensity Colors of Jeppeite in Air
Relative Intensity
0%
70%
100%
140%
210%
280%
350%
420%
490%
560%
630%
660%
R1
R2
Calculated Properties of Jeppeite
Electron Density:
Bulk Density (Electron Density)=3.68 gm/cc note: Specific Gravity of Jeppeite =3.94 gm/cc.
Fermion Index:
Fermion Index = 0.08 Boson Index = 0.92
Photoelectric:
PEJeppeite = 73.28 barns/electron U=PEJeppeite x relectron= 269.69 barns/cc.
Radioactivity:
GRapi = 98.56 (Gamma Ray American Petroleum Institute Units)
Concentration of Jeppeite per GRapi unit = 1.01 (%)
Estimated Radioactivity from Jeppeite - barely detectable
Jeppeite Classification
Dana Class:
08.07.09.01(08)Multiple Oxides with Nb, Ta, and Ti
Chemical Formula: 
- barely detectable