Fracture fillings in unaltered diamondiferous kimberlite found in drill cores.
IMA Status:
Approved IMA 1988
Locality:
Udachnaya pipe, Daldyn kimberlite field, Yakutiya, Russia. Link to MinDat.org Location Data.
Name Origin:
Named for the Institute of the Earth's Crust (Russian: zemnoy kory = "earth's crust"), Russian Academy of Science, Siberian Branch where the mineral was first studied.
Name Pronunciation:
Zemkorite + Pronunciation
Zemkorite Crystallography
Axial Ratios:
a:c = 1:1.26441
Cell Dimensions:
a = 10.06, c = 12.72, Z = 8; V = 1,114.84 Den(Calc)= 2.59
Fan Shaped - Occurs as radiating crystals shaped like a fan.
Habit:
Tabular - Form dimensions are thin in one direction.
Hardness:
2 - Gypsum
Luster:
Vitreous - Pearly
Streak:
white
Optical Properties of Zemkorite
Gladstone-Dale:
CI meas= -0.031 (Excellent) - where the CI = (1-KPDmeas/KC) CI calc= 0.021 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2023,KPDmeas= 0.213,KC= 0.2067 Ncalc = 1.51 - 1.54
Optical Data:
Uniaxial (-), e=1.513, w=1.535, bire=0.0220.
Calculated Properties of Zemkorite
Electron Density:
Bulk Density (Electron Density)=2.56 gm/cc note: Specific Gravity of Zemkorite =2.59 gm/cc.
Fermion Index:
Fermion Index = 0.0017091047 Boson Index = 0.9982908953
Photoelectric:
PEZemkorite = 3.48 barns/electron U=PEZemkorite x relectron= 8.91 barns/cc.
Radioactivity:
GRapi = 77.11 (Gamma Ray American Petroleum Institute Units)
Concentration of Zemkorite per GRapi unit = 1.30 (%)
Estimated Radioactivity from Zemkorite - barely detectable
Chemical Formula: 
- barely detectable