Mineral phase
IMA name
Pecoraite
Secondary names
Ni-bearing Chrysotile
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
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Ni$ Nickel element 3 constituent element main
$Si$ Silicon element 2 constituent element main
$O$ Oxygen element 9 constituent element main
$H$ Hydrogen element 4 constituent element main
Composition comments
Common impurities: Al, $Fe^{2+}$, Mg, Ca, H2O
Chemical functions
  Function Number
$(OH)^-$ 4
Chemical bonds
  Bond Number
$O^--H$ 1
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 (Chrysotile subgroup) (71.01.02d)
Code
71.01.02d.04
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/m
Molar mass
380.27 $g/mol$
Density
3.084 - 3.84 $g/cm^3$
State NTP
solid
Refringence type
biaxial
Refringence sign
positive or negative
Birefringence
0 - 0.038
Refraction index $n_{\alpha}$
1.565
Refraction index $n_{\beta}$
1.565 - 1.603
Refraction index $n_{\gamma}$
1.565 - 1.603
Dispersion V
strong r > v
Pure color
green
Color
blue-green, yellow-green, dark green
Diaphaneity
translucent
Luster
waxy