Named in honor of Chang Hung-chao (章鸿钊) (11 March 1877, Huzhou, Zhejiang Province, China - 6 September 1951, Nanjing, Jiangsu Province, China), geologist, mineralogist, and professor. He is considered one of the founders of modern Chinese geology and was a founder of the Chinese Geological Society.

Type Locality:

ⓘ Da Qaidam salt lake (Dachaidan salt lake), Da Qaidam (Dachaidan Co.), Haixi Mongol and Tibetan Autonomous Prefecture, Qinghai, China

This mineral has been reported from an undisclosed salt lake on the Qinghai-Tibet plateau (Zhu et al., 1964), a huge area that includes northern Tibet and northwestern Qinghai provinces. According to Yang (1991), Da Qaidam salt lake in Qinghai Province is the only occurrence of the mineral in that area.

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Unique IdentifiersHide

Mindat ID:

1950

Long-form identifier:

mindat:1:1:1950:3

IMA Classification of HungchaoiteHide

IMA status:

Approved

IMA Formula:

MgB₄O₅(OH)₄·7H₂O

First published:

1964

Type description reference:

Chun, I.H., Hsieh, H.T., Chien, T.C., Liu, L.P. (1964) Hungchaoite, a new hydrous magnesium borate. Acta Geologica Sinica: 44: 351-356.

Classification of HungchaoiteHide

Strunz-mindat (2026):

6.DA.20

6 : BORATES
D : Tetraborates
A : Neso-tetraborates

Dana 8th ed.:

26.4.3.1

26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
4 : Tetraborates

Hey's CIM Ref.:

9.2.12

9 : Borates
2 : Borates of Be and Mg

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference for Standard
Hch	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 HungchaoiteHide

Lustre:

Vitreous

Transparency:

Transparent

Colour:

Colorless

Hardness:

2½ on Mohs scale

Tenacity:

Brittle

Cleavage:

Perfect
{111}, perfect; {111}, good; {010}, imperfect.

Density:

1.706(5) g/cm³ (Measured) 1.703 g/cm³ (Calculated)

Optical Data of HungchaoiteHide

Type:

Biaxial (-)

RI values:

n_α = 1.445(2) n_β = 1.485(2) n_γ = 1.490(2)

2V:

Measured: 15° (2), Calculated: 36°

Max. Birefringence:

δ = 0.045
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.

Thickness: 30 µm Order divisions

Rotation:

Surface Relief:

Moderate (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).

This shows the grain boundary and Becke line effect under plane-polarised light, based on the contrast between this mineral's average refractive index and the mounting medium. It does not take into account mineral colouration.

Focus:

In focus

Interference Figure:

This shows the idealized biaxial acute bisectrix (Bxa) interference figure - the conoscopic view for a grain cut perpendicular to the acute bisectrix, using this mineral's 2V. The two small white dots mark the melatopes - the points where the two optic axes emerge - and are shown only when they fall within the field of view. The coloured bands are isochromatics, and the dark bands are isogyres.

Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.

Thickness: 30 µm

Stage rotation: 0°

Dispersion:

relatively strong

Chemistry of HungchaoiteHide

Mindat Formula:

Mg(B₄O₇) · 9H₂O

Element Weights:

Element	% weight
O	74.921 %
B	12.656 %
Mg	7.113 %
H	5.310 %

Calculated from ideal end-member formula.

Elements listed:

B, H, Mg, O - search for minerals with similar chemistry

Crystallography of HungchaoiteHide

Crystal System:

Triclinic

Class (H-M):

1 - Pinacoidal

Space Group:

Cell Parameters:

a = 8.807(1) Å, b = 10.657(1) Å, c = 7.897(1) Å
α = 103.39(1)°, β = 108.53(1)°, γ = 97.18(1)°

Ratio:

a:b:c = 0.826 : 1 : 0.741

Unit Cell V:

667.62 Å³ (Calculated from Unit Cell)

Crystal StructureHide

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CIF File Best | x | y | z | a | b | c

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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)
0000603	Hungchaoite	Wan C, Ghose S (1977) Hungchaoite, Mg(H2O)5B4O5(OH)4.2H2O: a hydrogen-bonded molecular complex American Mineralogist 62 1135-1143		1977		0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Hungchaoite'
loop_
_publ_author_name
'Wan C'
'Ghose S'
_journal_name_full 'American Mineralogist'
_journal_volume 62 
_journal_year 1977
_journal_page_first 1135
_journal_page_last 1143
_publ_section_title
;
 Hungchaoite, Mg(H2O)5B4O5(OH)4.2H2O: a hydrogen-bonded molecular complex
;
_database_code_amcsd 0000603
_chemical_formula_sum 'Mg B4 O16 H18'
_cell_length_a 8.807
_cell_length_b 10.657
_cell_length_c 7.897
_cell_angle_alpha 103.39
_cell_angle_beta 108.53
_cell_angle_gamma 97.18
_cell_volume 667.622
_exptl_crystal_density_diffrn      1.700
_symmetry_space_group_name_H-M 'P -1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Mg   0.82907   0.22643   0.13238 ?
B1   0.18120   0.30170   0.48350 ?
B2   0.22420   0.08300   0.52690 ?
B3   0.27860   0.27610   0.79260 ?
B4   0.46290   0.40940   0.68870 ?
O1   0.19150   0.16140   0.41060 ?
O2   0.27310   0.13220   0.71630 ?
O3   0.44370   0.35360   0.82190 ?
O4   0.34120   0.38930   0.52020 ?
O5   0.15450   0.31880   0.65960 ?
O-h1   0.05090   0.33050   0.33910 ?
O-h2   0.20540   0.95170   0.44280 ?
O-h3   0.25390   0.28930   0.99770 ?
O-h4   0.61320   0.48910   0.73260 ?
OW1   0.61080   0.11480   0.92720 ?
OW2   0.88760   0.04530   0.14250 ?
OW3   0.72460   0.21920   0.33870 ?
OW4   0.74150   0.39500   0.10710 ?
OW5   0.92680   0.22670   0.92570 ?
OW6   0.39750   0.15030   0.20390 ?
OW7   0.89190   0.41040   0.66400 ?
H1   0.07700   0.41300   0.34600   0.05300
H2   0.22700   0.90700   0.51000   0.06300
H3   0.29300   0.36600   0.04900   0.05500
H4   0.61900   0.52000   0.65100   0.04000
H5   0.51800   0.12700   0.86600   0.04900
H6   0.60900   0.02800   0.87700   0.06500
H7   0.83800   0.98700   0.17800   0.06400
H8   0.99400   0.05900   0.20800   0.05700
H9   0.61700   0.21100   0.30000   0.05800
H10   0.76200   0.29100   0.43200   0.06200
H11   0.77600   0.47500   0.18000   0.06500
H12   0.64900   0.39000   0.02300   0.03600
H13   0.03000   0.25000   0.94700   0.05800
H14   0.88300   0.16900   0.82300   0.05900
H15   0.34000   0.15600   0.26800   0.05000
H16   0.35700   0.19200   0.13300   0.06400
H17   0.97500   0.37900   0.66500   0.06000
H18   0.85800   0.40300   0.75500   0.05000
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Mg 0.01650 0.01930 0.01810 0.00280 0.00350 0.00670
B1 0.01330 0.01510 0.01510 0.00190 0.00350 0.00600
B2 0.02000 0.01720 0.01790 0.00530 0.00530 0.00610
B3 0.01520 0.01610 0.01370 0.00270 0.00480 0.00480
B4 0.01380 0.01710 0.01530 0.00210 0.00530 0.00430
O1 0.02070 0.01590 0.01440 0.00450 0.00500 0.00600
O2 0.02360 0.01480 0.01490 0.00420 0.00490 0.00550
O3 0.01270 0.02310 0.01490 0.00010 0.00250 0.00670
O4 0.01380 0.02180 0.01450 0.00160 0.00270 0.00770
O5 0.01240 0.01800 0.01520 0.00430 0.00520 0.00640
O-h1 0.01510 0.01620 0.01860 0.00140 0.00000 0.00800
O-h2 0.05950 0.01630 0.01940 0.00910 0.00820 0.00550
O-h3 0.02250 0.02030 0.01360 0.00050 0.00790 0.00400
O-h4 0.01630 0.02790 0.01580 0.00560 0.00370 0.00800
OW1 0.01830 0.02510 0.03040 0.00540 0.00190 0.00250
OW2 0.01980 0.02110 0.03110 0.00280 0.00400 0.01040
OW3 0.02040 0.02690 0.02360 0.00290 0.00720 0.00660
OW4 0.02740 0.02210 0.03110 0.00930 0.00440 0.00520
OW5 0.02370 0.03360 0.01990 0.00120 0.00900 0.00350
OW6 0.02260 0.02980 0.02600 0.00800 0.01120 0.00930
OW7 0.02520 0.02550 0.03590 0.01050 0.01430 0.01100

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
6.71 Å	(100)
3.356 Å	(92)
5.36 Å	(85)
4.093 Å	(78)
2.912 Å	(73)
4.079 Å	(64)
7.14 Å	(59)

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Near-surface Processes
25 : Evaporites (prebiotic)

Type Occurrence of HungchaoiteHide

Type Locality:

ⓘ Da Qaidam salt lake (Dachaidan salt lake), Da Qaidam (Dachaidan Co.), Haixi Mongol and Tibetan Autonomous Prefecture, Qinghai, China

Geological Setting of Type Material:

saline lacustrine sediments

Associated Minerals at Type Locality:

Reference:

Chun, I.H., Hsieh, H.T., Chien, T.C., Liu, L.P. (1964) Hungchaoite, a new hydrous magnesium borate. Acta Geologica Sinica: 44: 351-356.

Other Language Names for HungchaoiteHide

Dutch:Hungchaoiet

German:Hungchaoit

Russian:Хунчжаоит

Simplified Chinese:章氏硼镁石

Spanish:Hungchaoita

Traditional Chinese:章氏硼鎂石

Related Minerals - Strunz-mindat Grouping Hide

6.DA.10	Borax	Na₂(B₄O₅)(OH)₄ · 8H₂O	Mon. 2/m : B2/b
6.DA.15	Tincalconite	Na₂(B₄O₇) · 5H₂O	Trig. 32 : R32
6.DA.25	Roweite	Ca₂Mn²⁺₂B₄O₇(OH)₆	Orth. mmm(2/m2/m2/m) : Pbam
6.DA.25	Fedorovskite	Ca₂Mg₂B₄O₇(OH)₆	Orth. mmm(2/m2/m2/m) : Pbam
6.DA.30	Hydrochlorborite	Ca₄B₈O₁₅Cl₂ · 21H₂O	Mon. 2/m
6.DA.35	Uralborite	Ca₂[B₃O₃(OH)₅ · OB(OH)₃]	Mon. 2/m
6.DA.40	Numanoite	Ca₄Cu(B₄O₆(OH)₆)(CO₃)₂	Mon. 2/m : B2/m
6.DA.40	Borcarite	Ca₄Mg(B₄O₆(OH)₆)(CO₃)₂	Mon. 2/m : B2/m
6.DA.60	Fontarnauite	(Na,K)₂(Sr,Ca)(SO₄)[B₅O₈(OH)] · 2H₂O	Mon. 2/m : P2₁/b

Fluorescence of HungchaoiteHide

In UV light:

nonfluorescent

Other InformationHide

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 HungchaoiteHide

mindat.org URL:

https://www.mindat.org/min-1950.html
Please feel free to link to this page.

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External Links:

Look for Hungchaoite on Webmineral

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Look for Hungchaoite on Mineralien Atlas

Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for HungchaoiteHide

Reference List:

Chun, I.H., Hsieh, H.T., Chien, T.C., Liu, L.P. (1964) Preliminary report on the occurrence of a new hydrous magnesium borate - hungchaoite, MgO·2B2O3·9H2O, in China. Scientia Sinica: 13: 525-527. (in Russian)

Chun, I.H., Hsieh, H.T., Chien, T.C., Liu, L.P. (1964) Hungchaoite, a new hydrous magnesium borate. Acta Geologica Sinica: 44: 351-356.

Fleischer, Michael (1965) New Mineral Names. American Mineralogist, 50 (1-2) 261-268

IMA (1967) International Mineralogical Association: Commission on New Minerals and Mineral Names. Mineralogical Magazine and Journal of the Mineralogical Society, 36 (277) 131-136 doi:10.1180/minmag.1967.036.277.20

Tung Chi-ho (1974) X-ray powder photograph indexing and cell constant determination of hungtsaoite, a new mineral. Geochimica: 1974(3): 204-312 (in Chinese with English abstract). - American Mineralogist (1975), 50, 262 (abstract).

Wan, Che'ng, Ghose, Subrata (1977) Hungchaoite, Mg(H₂O)₅B₄O₅(OH)₄·2H₂O: a hydrogen bonded molecular complex. American Mineralogist, 62 (11-12) 1135-1143

Erd, Richard C., McAllister, James F., Eberlein, G. Donald (1979) New data on hungchaoite, the second world occurrence, Death Valley region, California. American Mineralogist, 64 (3-4) 369-375

Shaoxiu, Yang (1991) Saline Deposits And Minerals Of Salt Lakes In Qinghai-Xizang Plateau. Journal of Lake Sciences, 3 (1). 1-10 doi:10.18307/1991.0101

Grew, Edward S.; Anovitz, Lawrence M. - Eds. (1996) Boron - Mineralogy, Petrology and Geochemistry. Reviews in Mineralogy Vol. 33. Mineralogical Society of America p.862

(2005) Hungchaoite. Handbook of Mineralogy. Mineralogical Society of America

Localities for HungchaoiteHide

Showing 7 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the

symbol to view information about a locality. The

symbol next to localities in the list can be used to jump to that position on the map.

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Locality ListHide

- 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). ~~Struck out~~ - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.


China (TL)
Qinghai Haixi Mongol and Tibetan Autonomous Prefecture Da Qaidam (Dachaidan Co.) ⓘ Da Qaidam salt lake (Dachaidan salt lake) (TL)	Yihua Zhu et al. (1964) +3 other references

Kazakhstan
Atyrau Region Inder District ⓘ Inder B deposit and salt dome	Anatoly Kasatkin data

Romania
Maramureș County Târgu Lăpuș ⓘ Răzoare	HÎRTOPANU et al. (2025)

USA
California Inyo County Furnace Creek Mining District (Furnace Creek Borate Mining District) Ryan ⓘ Hard Scramble claim	Erd et al. (1970) +2 other references
Twenty Mule Team Canyon ⓘ Meridian claim	Erd et al. (1979) +2 other references
ⓘ South Meridian claim	Erd et al. (1979)
ⓘ Unnamed Borate occurrence [28]	Erd et al. (1979) +2 other references

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Hungchaoite

Unique IdentifiersHide

IMA Classification of HungchaoiteHide

Classification of HungchaoiteHide

Mineral SymbolsHide

Physical Properties of HungchaoiteHide

Optical Data of HungchaoiteHide

Chemistry of HungchaoiteHide

Crystallography of HungchaoiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of HungchaoiteHide

Other Language Names for HungchaoiteHide

Related Minerals - Strunz-mindat GroupingHide

Fluorescence of HungchaoiteHide

Other InformationHide

Internet Links for HungchaoiteHide

References for HungchaoiteHide

Localities for HungchaoiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide