Borate Mineral

The borate (BO₃) units may be polymerised similar to the SiO₄ unit of the silicate mineral class. This results in B₂O₅, B₃O₆, B₂O₄ anions as well as more complex structures which include hydroxide or halogen anions. The [B(O,OH)₄]⁻ anion exists as well.

Many borate minerals, such as borax, colemanite, and ulexite, are salts: soft, readily soluble, and found in evaporite contexts. However, some, such as boracite, are hard and resistant to weathering, more similar to the silicates.

There are over 100 different borate minerals. Borate minerals include:

• Kernite Na₂B₄O₆(OH)₂·3H₂O
• Borax Na₂B₄O₅(OH)₄·8H₂O
• Ulexite NaCaB₅O₆(OH)₆·5H₂O
• Colemanite CaB₃O₄(OH)₃·H₂O
• Boracite Mg₃B₇O₁₃Cl
• Painite CaZrAl₉O₁₅(BO₃)

IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 2009). This list uses it to modify the Classification of Nickel–Strunz (mindat.org, 10 ed, pending publication). Note that although Nickel–Strunz division letters were traditionally based on the number of boron atoms in a mineral's chemical formula (06.A are monoborates, 06.B are diborates, etc.), the IMA has reclassified borate minerals based on the polymerisation of the borate anion.

Abbreviations

• REE: rare-earth element (Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)
• PGE: platinum-group element (Ru, Rh, Pd, Os, Ir, Pt)
• * : discredited (IMA/CNMNC status)
• ? : questionable/doubtful (IMA/CNMNC status)

Regarding 03.C Aluminofluorides, 06 Borates, 08 Vanadates (04.H V^[5,6] Vanadates), 09 Silicates:

• neso-: insular (from Greek νῆσος nêsos, "island")
• soro-: grouped (from Greek σωρός sōrós, "heap, pile, mound")
• cyclo-: rings of (from Greek κύκλος kúklos, "circle")
• ino-: chained (from Greek ίνα ína, "fibre", [from Ancient Greek ἴς])
• phyllo-: sheets of (from Greek φῠ́λλον phúllon, "leaf")
• tekto-: three-dimensional framework (from Greek τεκτονικός tektōnikós, "of building")

Nickel–Strunz code scheme: NN.XY.##x

• NN: Nickel–Strunz mineral class number
• X: Nickel–Strunz mineral division letter
• Y: Nickel–Strunz mineral family letter
• ##x: Nickel–Strunz mineral/group number; x an add-on letter

Class: borates

• 06. Alfredstelznerite
• 06.A Monoborates
  • 06.AA BO₃, without additional anions; 1(D): 05 Sassolite; 15 Nordenskioldine, 15 Tusionite; 35 Jimboite, 35 Kotoite; 40 Takedaite
  • 06.AB BO₃, with additional anions; 1(D) + OH, etc.: 05 Hambergite, 10 Berborite, 15 Jeremejevite; 20 Warwickite, 20 Yuanfuliite; 25 Karlite; 30 Azoproite, 30 Bonaccordite, 30 Fredrikssonite, 30 Ludwigite, 30 Vonsenite; 35 Pinakiolite; 40 Blatterite, 40 Orthopinakiolite, 40 Takeuchiite, 40 Chestermanite; 45 Hulsite, 45 Magnesiohulsite, 45 Aluminomagnesiohulsite; 50 Hydroxylborite, 50 Fluoborite; 55 Shabynite, 55 Wightmanite; 60 Gaudefroyite, 65 Sakhaite, 70 Harkerite; 75 IMA2008-060, 75 Pertsevite; 80 Jacquesdietrichite, 85 Painite
  • 06.AC B(O,OH)₄, without and with additional anions; 1(T), 1(T)+OH, etc.: 05 Sinhalite; 10 Pseudosinhalite; 15 Béhierite, 15 Schiavinatoite; 20 Frolovite; 25 Hexahydroborite; 30 Henmilite; 35 Bandylite; 40 Teepleite; 45 Moydite-(Y); 50 Carboborite; 55 Sulfoborite; 60 Luneburgite; 65 Seamanite; 70 Cahnite
• 06.H Unclassified Borates
  • 06.HA Unclassified borates: 05 Chelkarite; 10 Braitschite-(Ce); 15 Satimolite; 20 Iquiqueite; 25 Wardsmithite; 30 Korzhinskite; 35 Halurgite; 40 Ekaterinite; 45 Vitimite; 50 Canavesite; 55 Qilianshanite

Subclass: nesoborates

• 06.BA Neso-diborates with double triangles B₂(O,OH)₅; 2(2D); 2(2D) + OH, etc.: 05 Suanite; 10 Clinokurchatovite, 10 Kurchatovite; 15 Sussexite, 15 Szaibelyite; 20 Wiserite
• 06.BB Neso-diborates with double tetrahedra B₂O(OH)₆; 2(2T): 05 Pinnoite; 10 Pentahydroborite
• 06.CA Neso-triborates: 10 Ameghinite; 15 Inderite; 20 Kurnakovite; 25 Inderborite; 30 Meyerhofferite; 35 Inyoite; 40 Solongoite; 45 Peprossiite-(Ce); 50 Nifontovite; 55 Olshanskyite
• 06.DA Neso-tetraborates: 10 Borax; 15 Tincalconite; 20 Hungchaoite; 25 Fedorovskite, 25 Roweite; 30 Hydrochlorborite; 35 Uralborite; 40 Numanoite, 40 Borcarite; 60 Fontarnauite
• 06.EA Neso-pentaborates: 05 Sborgite; 10 Ramanite-(Rb), 10 Ramanite-(Cs), 10 Santite; 15 Ammonioborite; 25 Ulexite
• 06.FA Neso-hexaborates: 05 Aksaite; 10 Mcallisterite; 15 Admontite; 20 Rivadavite; 25 Teruggite

Subclass: inoborates

• 06.BC Ino-diborates with triangles and/or tetrahedra: 10 Calciborite, 10 Aldzhanite*; 15 Vimsite; 20 Sibirskite, 20 Parasibirskite
• 06.CB Ino-triborates: 10 Colemanite; 15 Hydroboracite; 20 Howlite; 25 Jarandolite
• 06.DB Ino-tetraborates: 05 Kernite
• 06.EB Ino-pentaborates: 05 Larderellite; 10 Ezcurrite; 15 Probertite; 20 Tertschite; 25 Priceite
• 06.FB Ino-hexaborates: 05 Aristarainite; 10 Kaliborite

Subclass: phylloborates

• 06.CC Phyllo-triborates: 05 Johachidolite
• 06.EC Phyllo-pentaborates: 05 Biringuccite, 05 Nasinite; 10 Gowerite; 15 Veatchite, 15 Veatchite-A, 15 Veatchite-p; 20 Volkovskite; 25 Tuzlaite; 30 Heidornite; 35 Brianroulstonite
• 06.FC Phyllo-hexaborates: 05 Nobleite, 05 Tunellite, 05 Balavinskite; 10 Strontioborite; 15 Ginorite, 15 Strontioginorite; 20 Fabianite
• 06.GB Phyllo-nonaborates, etc.: 05 Studenitsite; 10 Penobsquisite; 15 Preobrazhenskite; 20 Walkerite

Subclass: tektoborates

• 06.BD Tektodiborates with tetrahedra: 05 Santarosaite
• 06.DD Tekto-tetraborates: 05 Diomignite
• 06.ED Tekto-pentaborates: 05 IMA2007-047, 05 Tyretskite, 05 Hilgardite, 05 Kurgantaite
• 06.GA Tekto-heptaborates: 05 Boracite, 05 Chambersite, 05 Ericaite; 10 Congolite, 10 Trembathite
• 06.GC Tekto-dodecaborates: 05 Rhodizite, 05 Londonite
• 06.GD Mega-tektoborates: 05 Ruitenbergite, 05 Pringleite; 10 Metaborite

• Classification of minerals - Non-silicates
• Classification of minerals - Silicates