Boracite
A valid IMA mineral species - grandfathered
This page kindly sponsored by Alfredo Petrov
About Boracite
Formula:
Mg3(B7O13)Cl
Colour:
Green, blue, colourless, grey, white; dark green (ferroan); colourless in transmitted light
Lustre:
Adamantine, Vitreous
Hardness:
7 - 7½
Specific Gravity:
2.91 - 3.1
Crystal System:
Orthorhombic
Member of:
Name:
Named in allusion to the composition, containing BORon.
Dimorph of:
Boracite Group. Boracite-Ericaite Series. The magnesium analogue of Ericaite and Chambersite. The orthorhombic dimorph of Trembathite.
Boracite is found in evaporite deposits, usually associated with gypsum, anhydrite and/or halite.
Visit gemdat.org for gemological information about Boracite.
Boracite is found in evaporite deposits, usually associated with gypsum, anhydrite and/or halite.
Visit gemdat.org for gemological information about Boracite.Unique Identifiers
Mindat ID:
721
Long-form identifier:
mindat:1:1:721:2
IMA Classification of Boracite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Mg3B7O13Cl
Classification of Boracite
6.GA.05
6 : BORATES
G : Heptaborates and other megaborates
A : Tekto-heptaborates
6 : BORATES
G : Heptaborates and other megaborates
A : Tekto-heptaborates
Dana 7th ed.:
25.6.1.1
25.6.1.1
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
10.1.5
10 : Borates with other anions
1 : Borates with halide
10 : Borates with other anions
1 : Borates with halide
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Boc | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Boracite
Adamantine, Vitreous
Transparency:
Transparent, Translucent
Colour:
Green, blue, colourless, grey, white; dark green (ferroan); colourless in transmitted light
Comment:
Very rarely pink, yellow.
Streak:
White
Hardness:
7 - 7½ on Mohs scale
Cleavage:
None Observed
Fracture:
Irregular/Uneven, Conchoidal
Density:
2.91 - 3.1 g/cm3 (Measured) 2.97 g/cm3 (Calculated)
Optical Data of Boracite
Type:
Biaxial (+)
RI values:
nα = 1.658 - 1.662 nβ = 1.662 - 1.667 nγ = 1.668 - 1.673
2V:
Measured: 82°
Max. Birefringence:
δ = 0.010 - 0.011
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
Surface Relief:
Moderate
Dispersion:
weak
Chemistry of Boracite
Mindat Formula:
Mg3(B7O13)Cl
Element Weights:
Elements listed:
Common Impurities:
Fe(II)
Crystallography of Boracite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pca21
Cell Parameters:
a = 8.577(6) Å, b = 8.553(8) Å, c = 12.09(1) Å
Ratio:
a:b:c = 1.003 : 1 : 1.414
Unit Cell V:
882.47 ų
Z:
4
Morphology:
Crystals usually isolated in matrix; less often in groups. Small individuals may project from the face-centers of larger single crystals. Often cubic; also dodecahedral, tetrahedral; pseudo-octahedral or cuboctahedral with {111} commonly larger and brighter than {111}. Fine granular, fibrous to plumose aggregates. NOTE: above 265° the crystal system is isometric-hex'tetrahedral - 43_m.
Twinning:
On {111} as penetration twins, rare.
Crystallographic forms of Boracite
Crystal Atlas:
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Boracite no.2 - Goldschmidt (1913-1926)
Boracite no.5 - Goldschmidt (1913-1926)
Boracite no.41 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000382 | Boracite | Sueno S, Clark J R, Papike J J, Konnert J A (1973) Crystal-structure refinement of cubic boracite American Mineralogist 58 691-697 |  | 1973 | Solvayshall, Roschwitz, Germany | 0 | 673 |
| 0019539 | Boracite | Ito T, Morimoto N, Sadanaga R (1951) The crystal structure of boracite Acta Crystallographica 4 310-316 |  | 1951 | Stassfurt, Germany | 0 | 293 |
| 0019540 | Boracite | Ito T, Morimoto N, Sadanaga R (1951) The crystal structure of boracite Acta Crystallographica 4 310-316 | | 1951 | Stassfurt, Germany | 0 | 573 |
| 0010744 | Boracite | Dowty E, Clark J R (1973) Crystal-structure refinements for orthorhombic boracite, Mg3B7O13Cl, and a trigonal, iron-rich analogue Zeitschrift fur Kristallographie 138 64-99 | | 1973 | Solvayshall, Roschwitz, Germany | 0 | 293 |
| 0018134 | Boracite | Mehmel M (1932) Kristallstrukturelle Untersuchungen an Borazit _cod_database_code 1011284 Fortschritte der Mineralogie 17 436-438 | 1932 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.044 Å | (100) |
| 3.025 Å | (88) |
| 2.705 Å | (55) |
| 3.492 Å | (45) |
| 2.137 Å | (30) |
| 6.050 Å | (27) |
| 2.468 Å | (21) |
Comments:
England. Data from Burns (1995).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Geological Setting:
Bedded sedimentary deposits of gypsum and anhydrite; salt deposits; potash deposits of the oceanic type.
Type Occurrence of Boracite
Place of Conservation of Type Material:
Mining academy of Freiberg 19324
Geological Setting of Type Material:
Bedded sedimentary deposit of gypsum and anhydrite.
Associated Minerals at Type Locality:
Synonyms of Boracite
Other Language Names for Boracite
Dutch:Boraciet
German:Boracit
b-Boracit
Borazit
Kubische Quarzkrystalle
Lüneburger Sedativ-Spath
Metaboracit
Parasit
Würfelstein
b-Boracit
Borazit
Kubische Quarzkrystalle
Lüneburger Sedativ-Spath
Metaboracit
Parasit
Würfelstein
Italian:Boracite
Polish:Boracyt
Russian:Борацит
Simplified Chinese:方硼石
Traditional Chinese:方硼石
Varieties of Boracite
| Bromboracit | Artificial Bromine analogue of Boracite |
| Iron-bearing Boracite | |
| Stassfurtite | A fibrous variety of Boracite from Stassfurt, Germany. |
Relationship of Boracite to other Species
Member of:
Other Members of Boracite Group:
| Chambersite | Mn2+3(B7O13)Cl | Orth. mm2 : Pca21 |
| Congolite | (Fe2+,Mg)3(B7O13)Cl | Trig. 3m : R3c |
| Ericaite | Fe2+3(B7O13)Cl | Orth. mm2 : Pca21 |
| Trembathite | (Mg,Fe)3(B7O13)Cl | Trig. 3m : R3c |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
| 93 photos of Boracite associated with Hilgardite | Ca2B5O9Cl · H2O |
| 29 photos of Boracite associated with Anhydrite | CaSO4 |
| 7 photos of Boracite associated with Pyrite | FeS2 |
| 4 photos of Boracite associated with Chromite | Fe2+Cr3+2O4 |
| 4 photos of Boracite associated with Hilgardite-3Tc | Ca2B5O9Cl · H2O |
| 3 photos of Boracite associated with Magnesite | MgCO3 |
| 2 photos of Boracite associated with Ericaite | Fe2+3(B7O13)Cl |
| 2 photos of Boracite associated with Gypsum | CaSO4 · 2H2O |
| 2 photos of Boracite associated with Halite | NaCl |
| 1 photo of Boracite associated with Preobrazhenskite | Mg3B11O15(OH)9 |
Related Minerals - Strunz-mindat Grouping
| 6.GA.05 | Ericaite | Fe2+3(B7O13)Cl |
| 6.GA.05 | Chambersite | Mn2+3(B7O13)Cl |
| 6.GA.10 | Congolite | (Fe2+,Mg)3(B7O13)Cl |
| 6.GA.10 | Trembathite | (Mg,Fe)3(B7O13)Cl |
| 6.GA.30 | Korzhinskite | Ca(B2O4) · H2O |
Other Information
Electrical:
Strongly piezoelectric and pyroelectric.
Thermal Behaviour:
Pyroelectric. At 265° the crystal system reverts to a high-temperature phase and the material becomes isotropic.
Notes:
Slowly but completely soluble in HCl. Very slowly decomposed by water.
Forms pseudomorphs after quartz (Douglashall).
Forms pseudomorphs after quartz (Douglashall).
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Boracite
mindat.org URL:
https://www.mindat.org/min-721.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Boracite
Reference List:
Dana, James D., Brush, George Jarvis (1868) A System of Mineralogy (5th ed.). p.882pages 596, 799 (as Huyssenite, Iron-boracite)
Bøggild, Ο. B. (1912) Krystallform und Zwillingsbildungen des Kryoliths, des Perowskits und des Boracits. Zeitschrift für Kristallographie, 50 (1-6). 349-429 doi:10.1524/zkri.1912.50.1.349
Dowty, Eric; Clark, Joan E. (1973) Crystal-structure refinements for orthorhombic boracite, Mg3ClB7O13, and a trigonal, iron-rich analogue. Zeitschrift für Kristallographie, 138 (1-4). 64-99 doi:10.1524/zkri.1973.138.1-4.64
Localities for Boracite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Afghanistan | |
| Tucker et al. (2012) |
Australia | |
| Bottrill |
Bolivia | |
| Wilson (2001) |
| - (unpublished thesis) |
| Petrov (n.d.) |
| Federico Ahlfeld and Alfredo Petrov ... |
Canada | |
| Grice et al. (1996) +2 other references |
| Anderle et al. (1979) |
| Grice et al. (2005) |
| Boehner (1986) |
Chile | |
| Lohmeier et al. (2025) |
China | |
| She et al. (2022) |
| Xiao et al. (2022) |
| Liu et al. (2025) |
| Li et al. (2024) |
| Niu et al. (2024) |
| Jiang et al. (2025) |
| Xiaosong Xu and Jialing Wu (1983) +1 other reference |
France | |
| Palache et al. (1951) |
Germany | |
| Weiß (1990) |
| Braitsch (1961) |
| |
| Weiß (1990) |
| Palache et al. (1951) |
| Weiß (1990) |
| Gerstenberg (n.d.) |
| Emser Hefte 1990 (1) |
| Palache et al. (1951) |
| Aufschluss 1987 (4) |
| Lavinsky (n.d.) |
| Hoffmann (1789) +3 other references |
| Palache et al. (1951) | |
| www.mineralienatlas.de (n.d.) |
| Mineralogical Society of America - ... |
| Wand et al. (1989) +3 other references |
| Feit (1889) +1 other reference |
| Palache et al. (1951) +1 other reference |
| Günther (1999) | |
| ... |
| Naumann +1 other reference | |
| Palache et al. (1951) | |
| Brockt et al. (2001) |
| Mineralogical Society of America - ... |
| Naumann +1 other reference | |
| ... | |
| Palache et al. (1951) +1 other reference |
| Zeitschrift fUr Kristallographie et al. (1973) +1 other reference |
| Christian Bracke and M. Kampf specimens |
| Effmert +1 other reference |
| Heide et al. (1964) |
Kazakhstan | |
| Handbook of Mineralogy Vol V p 6 +5 other references |
| Pekov et al. (1993) +2 other references |
| Mineralogical Society of America - ... +2 other references |
Laos | |
| GAO et al. (2012) |
Poland | |
| Jirásek +7 other references |
| Praszkier (2010) |
| Kucha (1979) +1 other reference |
Republic of the Congo | |
| Henry Rauche (2009) |
Russia | |
| Vladykin et al. (2017) |
| Pekov et al. (2001) +2 other references |
| Mazurov et al. (2007) |
South Africa | |
| Rozendaa et al. (2012) |
Thailand | |
| Suwanich (2010) |
UK | |
| BMS Collection +3 other references |
| Palache et al. (1951) |
| Smith et al. (2014) |
| Smith et al. (2014) | |
| Kemp et al. (2016) | |
USA | |
| Mineralogical Society of America - ... |
| Rocks & Min.: 64:472. +1 other reference | |
| Justin Zzyzx specimen |
| Error in 1930s State publication |
| Smith (1994) |
| American Mineralogist 23:898 +1 other reference |
| Smith (1994) |
| R&M 69:3 pp 156-162 | |
| Smith (1994) | |
| Van Rythoven et al. (2020) |
| Hutchinson et al. (2022) |
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Lüneburger Kalkberg, Lüneburg, Lüneburg District, Lower Saxony, Germany