Ulexite

A rare sodium-calcium borate. Most specimens of ulexite are fibrous in nature. Most of the time, the fibers are intergrown into felt-like aggregates. Most familiar to collectors is the kind of ulexite that is popularly called "TV rock" because of its natural fiber optic character. Less well known forms are the acicular variety that can make for spectacular specimens and the form that is called "clam shell" ulexite.

History

Activities related to discovery and approval of the group members

Structural context

Ulexite
Crystal System triclinicCrystal Class pinacoidalSpace Group P-1
a8.805—8.816 (8.8089)
b12.855—12.87 (12.8602)
c6.6648—6.678 (6.6692)
alpha90.28—90.36 (90.3117)
beta109.05—109.09 (109.0723)
gamma104.98—105.035 (105.014)
volume685.181—688.445 (686.3017)

Based on 3 measurements

Chemical context

Stoichiometric formulas

Ulexite
mindat.org
  • March 13, 2023NaCa[B5O6(OH)6]·5H2O
IMA
  • March 13, 2023NaCaB5O6(OH)6 · 5H2O
mineralogy.rocks
  • Aug. 30, 2022NaCaB5O6(OH)6·5H2O

Elements recorded on EPMA

2
B
2
Ca
2
H
2
Na
2
O

Physical properties

ColorColor entities, recognized using a custom trained NER model
  • colourless
      Color noteOriginal color note from the source
      Colourless, white, grey with included clays.
      Lustre
      Vitreous
      Silky
      Fracture
      Irregular/Uneven
      Transparency
      Transparent
      Tenacity
      brittle
      Hardness
      2.5
      Calculated density
      1.955