Mineral phase
- IMA name
- Nepouite
- Secondary names
- Genthite
- Class
- silicate mineral
- Compound type
- phyllosilicate
- Formula
- $Ni_3.Si_2O_5(OH)_4$
- Chemical formula
- Ni3Si2O5(OH)4
- Elemental formula
- Ni3 Si2 O9 H4
- Isotope mixture type
- terrestrial abundance
- Composition comments
- Common substitution of Ni: Mg (sometimes in the formula: $(Ni,Mg)_3.Si_2O_5(OH)_4$) - Common impurities: Al, Fe, Ca, Na, K
- Oxides
-
Formula $NiO$ $SiO_{2}$ $H_{2}O$ Mass fraction (%) 58.92 31.6 9.48
Strunz
- Class
- silicates (09)
- Division
- phyllosilicate (09.E)
- Family
- with kaolinite layers composed of tetrahedral and octahedral nets (09.ED)
- Code
- 09.ED.15
Dana
- Major class
- silicates (VIII)
- Class
- phyllosilicate sheets of six-membered rings (71)
- Type
- with 1:1 layers (71.01)
- Group
- Serpentine group (Lizardite subgroup) (71.01.02b)
- Code
- 71.01.02b.03
- Phase type
- crystalline
- Crystal system
- orthorhombic
- Crystal class
- pyramidal
- Crystal class symbol
- mm2 (C2v)
- Crystal spacegroup
- Cmc2(1)
- Molar mass
- 380.27 $g/mol$
- Density
- 2.5 - 3.2 $g/cm^3$
- State NTP
- solid
- Refringence type
- biaxial
- Refringence sign
- negative
- Birefringence
- 0.020 - 0.035
- Refraction index $n_{\alpha}$
- 1.60 - 1.63
- Refraction index $n_{\beta}$
- 1.576 - 1.579
- Refraction index $n_{\gamma}$
- 1.635 - 1.65
- Dispersion V
- r > v medium
- Pure color
- green
- Color
- pale green, deep green
- Diaphaneity
- translucent to subtranslucent
- Luster
- vitreous