Mineral phase
IMA name
Nobleite
Class
non-silicate mineral
Compound type
borate
Formula
CaB6O9(OH)23(H2O)
Chemical formula
CaB6O9(OH)2•3(H2O)
Elemental formula
(Ca2+) B6 O12 H8 (O-)2
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
Ca2+ Calcium cation element 1 constituent cation main
B Boron element 6 constituent element main
O Oxygen element 9 constituent element main
(OH) Hydroxide anion chemical function 2 anionic radical main
H2O Water molecule 3 hydration main
Chemical functions
  Function Number
(OH) 2
ROH 2
Chemical bonds
  Bond Number
>BO 12
BO 8
OH 2
OH 1
Oxides
Formula CaO B2O3 H2O
Mass fraction (%) 16.64 61.98 21.38

Strunz

Class
borates (06)
Division
hexaborates (06.F)
Family
Phyllo-hexaborates (06.FC)
Code
06.FC.05

Dana

Major class
carbonates, nitrates, borates (V)
Class
hydrated borates containing hydroxyl or halogen (26)
Type
26.06
Group
-Nobleite- group (26.06.06)
Code
26.06.06.01
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
P2(1)/c
Molar mass
336.99 g/mol
Density
2.09 g/cm3
State NTP
solid
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.054
Refraction index nα
1.5
Refraction index nβ
1.52
Refraction index nγ
1.554
Pure color
colorless
Color
colorless, white
Diaphaneity
transparent
Luster
vitreous