The hornblende root name is in a mineralogical sense as amphiboles in the calcium amphibole subgroup with ^A(Na+K+2Ca)≤0.5 apfu and 0,5≤^Z(Al + Fe³⁺ +2Ti)≤1.5 apfu. The individual members of the group are defined by their dominant elements in the Z and W positions:

Z²⁺ position (= IMA C²⁺ position): Mg or Fe²⁺
Z³⁺ position (= IMA C³⁺ position): Al or Fe³⁺
W position: (OH) or F

On mindat.org we avoid using variables with the same symbol as elements and deviate from the IMA nomenclaure in that we use X rather than B, Z rather than C and (OH,F,Cl,O) rather than W.

The hornblende root name is an IMA-CNMNC defined amphibole root-name with strict chemical boundaries. It should not be confused with the more loosely defined "hornblende", which is a term used by petrologists and mineral collectors for any black or dark coloured undefined amphibole in the calcium (and sometimes in the sodium-calcium) subgroups.

Unique IdentifiersHide

Mindat ID:

8789

Long-form identifier:

mindat:1:1:8789:2

Chemistry of Hornblende Root Name GroupHide

Mindat Formula:

◻Ca₂(Z²⁺₄Z³⁺)(AlSi₇O₂₂)(OH,F,Cl)₂

Age distributionHide

Recorded ages:

Anthropocene : 0 Ma to 38 Ma - based on 16 recorded ages.

Sample ages:

Sample ID	Recorded age	Geologic Time	Dating method
1	At least Ma	Anthropocene

Sample references:

ID	Locality	Reference	Notes
1	Lục Yên District, Yên Bái Province, Vietnam	Garnier, V., Ohnenstetter, D., Giuliani, G., Maluski, H., Deloule, E., Trong, T. P., Pham Van, L., Hoang Quang, V. (2005) Age and significance of ruby-bearing marble from the Red River Shear Zone, northern Vietnam. The Canadian Mineralogist, 43 (4). 1315-1329 doi:10.2113/gscanmin.43.4.1315

Chemical AnalysisHide

Oxide wt%:

Showing 12 of 16 analyses on this page.

	1	2	3	4	5	6	7	8	9	10	11	12
SiO₂	39.94 %	48.15 %	42.91 %	58.66 %	47.89 %	48.48 %	53.43 %	49.95 %	47.06 %	49.05 %	43.68 %	49.7 %
TiO₂	0.2 %	0.3 %	0.15 %	0.09 %	0.33 %	0.20 %	0.13 %	0.63 %	1.27 %	0.32 %
Al₂O₃	16.02 %	10.22 %	14.70 %	3.37 %	9.19 %	13.70 %	7.22 %	11.07 %	12.20 %	8.35 %	5.33 %	10.53 %
FeO	22.06 %	10.66 %	20.29 %	7.03 %	14.13 %	7.87 %	5.66 %	9.44 %	15.52 %	27.96 %	0.8 %
MnO	0.31 %	0.18 %	0.06 %	0.1 %	0.03 %	0.13 %	0.11 %	0.07 %	0.98 %
MgO	5,29 %	14.28 %	6.05 %	16.48 %	13.32 %	14.84 %	17.87 %	14.16 %	10.61 %	15.45 %	5.55 %	20.57 %
CaO	11.45 %	11.51 %	8.94 %	10.20 %	10.97 %	10.18 %	11.01 %	9.45 %	9.12 %	12.07 %	10.27 %	12.59 %
Na₂O	1.52 %	1.59 %	3.67 %	2.07 %	2.13 %	3.74 %	1.96 %	3.66 %	3.76 %	1.07 %	1.29 %	1.55 %
K₂O	0.52 %	0.29 %	0.34 %	0.11 %	0.38 %	0.20 %	0.02 %	0.28 %	0.76 %	0.14 %
Cr₂O₃	0.02 %	0.12 %	0.03 %	0.05 %
NiO	0.01 %
H₂O	1.97 %	2.18 %	2.02 %
Fe₂O₃
BaO
F	0.34 %	0.25 %
Cl	0.03 %
FeOt	9.82 %
ZrO	0.08 %
Total:	97.02 %	97.18 %	99.08 %	100.31 %	97.97 %	99.55 %	97.15 %	98.38 %	98.56 %	96.84 %	97.09 %	98.59 %

Empirical formulas:

Sample ID	Empirical Formula
1	(Na_0.381K_0.101)_Σ0.482 (Ca_1.872Na_0.069Mn_0.04Fe_0.019)_Σ2 (Fe²⁺_2.282Mg_1.204Al_0.977Fe³⁺_0.514Ti_0.023)_Σ5 (Si_6.095Al_1.905)_Σ8 O₂₂ ((OH)_1.954O_0.046)_Σ2
2	(Na_0.283K_0.053)_Σ0.336 (Ca_1.775Na_0.16Fe_0.043Mn_0.022)_Σ2 (Mg_3.064Fe²⁺_1.01Al_0.663Fe³⁺_0.23Ti_0.032)_Σ4.999 (Si_6.93Al_1.07)_Σ8 O₂₂ ((OH)_1.935O_0.065)_Σ2
7	Na_0.17(Na_0.36Ca_1.64)_Σ2.00 ( Mg_3.71Fe²⁺_0.55Fe³⁺_0.11Al_0.63)_Σ5.00(Al_0.56Si_7.44)_Σ8.00O₂₂OH₂
13	Na_0.05 (Na_0.22Ca_1.78)_Σ2.00 ( Mg_3.17Fe²⁺_0.98Fe³⁺_0.22Al_0.64)_Σ5.01(Al_0.68Si_7.32)_Σ8.00O₂₂OH₂
8	(Na_0.43 K_0.04 )_Σ0.47 (Na_0.57Ca_1.43)_Σ2.00 ( Mg_2.98 Mn_0.02Fe²⁺_1.12 Cr_0.01Ti_0.02Al_0.90)_Σ5.05(Al_0.94Si_7.06)_Σ8.00O₂₂OH₂
9	(Na_0.48 K_0.01 )_Σ0.49 (Na_0.58Ca_1.42)_Σ2.00 ( Mg_2.30Mn_0.01Fe²⁺_1.89 Ti_0.01Al_0.93)_Σ5.15(Al_1.16Si_6.84)_Σ8.00O₂₂OH₂
10	(Na_0.15 K_0.05 )_Σ0.20 (Na_0.15Ca_1.85)_Σ2.00 ( Mg_3.30Mn_0.01Fe²⁺_0.97 Fe³⁺_0.33Ti_0.07Al_0.44)_Σ5.12(Al_0.97Si_7.03)_Σ8.00O₂₂(OH)₂

Sample references:

ID	Locality	Reference	Notes
1	Engebøfjellet Eclogite Deposit, Naustdal, Sunnfjord, Vestland, Norway	Braathen, Alvar, Erambert, Muriel (2014) Structural and metamorphic history of the Engebøfjellet Eclogite and the exhumation of the Western Gneiss Region, Norway. Norwegian Journal of Geology - Norsk Geologisk Tidsskrift, 94 (1) 53-76	Retrograde amphibole as rims on clinopyroxene Formula normalized by use of Locock, A. J. (2014). An Excel spreadsheet to classify chemical analyses of amphiboles following the IMA 2012 recommendations. Computers & Geosciences, 62, 1-11.
2	" "	Braathen, Alvar, Erambert, Muriel (2014) Structural and metamorphic history of the Engebøfjellet Eclogite and the exhumation of the Western Gneiss Region, Norway. Norwegian Journal of Geology - Norsk Geologisk Tidsskrift, 94 (1) 53-76	Retrograde amphibole as rims on clinopyroxene Formula normalized by use of Locock, A. J. (2014). An Excel spreadsheet to classify chemical analyses of amphiboles following the IMA 2012 recommendations. Computers & Geosciences, 62, 1-11.
3	Akeyazhi River valley, Ili Kazakh Autonomous Prefecture, Xinjiang, China	Gao, J., Klemd, R., Zhang, L., Wang, Z., & Xiao, X. (1999). PT path of high-pressure/low-temperature rocks and tectonic implications in the western Tianshan Mountains, NW China. Journal of Metamorphic Geology, 17, 621-636.	Sample from eclogite
4	Sierra de las Minas, Motagua Valley, Guatemala	Harlow, G.E.; Sisson, V.B.; Sorensen, S.S. (2011) Jadeitite from Guatemala: new observations and distinctions among multiple occurrences. Geologica Acta, 9 (3-4). 363-387 doi:10.1344/105.000001694	Sample form a late vein in a retrograded jadeitite
5	Changpu, Yuexi County, Anqing, Anhui, China	Proyer, A., Rolfo, F., Castelli, D., & Compagnoni, R. (2014). Diffusion-controlled metamorphic reaction textures in an ultrahigh-pressure impure calcite marble from Dabie Shan, China. European Journal of Mineralogy, 26(1), 25-40.	Sample from a corona around omphacite from a retrograded eclogite
6	Gablor Hill eclogites, Kulp district, Diyarbakir Province, Turkey	Okay, A. I.; Arman, M. B.; Göncüoglu, M. C. (1985) Petrology and phase relations of the kyanite-eclogites from eastern Turkey. Contributions to Mineralogy and Petrology, 91 (2). 196-204 doi:10.1007/bf00377767	Pale-brown porphyroblastic grains in quartz-eclogite. EMPA analysis
7	Charakoma eclogite, Soufli, Evros, Eastern Macedonia and Thrace, Greece	Mposkos, E.; Baziotis, I.; Proyer, A. (2011) Pressure–temperature evolution of eclogites from the Kechros complex in the Eastern Rhodope (NE Greece). International Journal of Earth Sciences, 101 (4). 973-996 doi:10.1007/s00531-011-0699-2	EMPA analysis of an amphibole occurring as a symplectitic intergrowth with plagioclase. The symplectite is a retrograde alteration of omphacite in a kyanite-eclogite.
8	Eissee eclogite, Timmelbach valley, Prägraten am Großvenediger, Lienz District, Tyrol, Austria	Hoschek, Gert (2004) Comparison of calculated P-T pseudosections for a kyanite eclogite from the Tauern Window, Eastern Alps, Austria. European Journal of Mineralogy, 16 (1) 59-72 doi:10.1127/0935-1221/2004/0016-0059	EMPA analysis of a matrix amphibole from a kyanite-eclogite
9	" "	Hoschek, Gert (2004) Comparison of calculated P-T pseudosections for a kyanite eclogite from the Tauern Window, Eastern Alps, Austria. European Journal of Mineralogy, 16 (1) 59-72 doi:10.1127/0935-1221/2004/0016-0059	EMPA analysis of an inclusion in garnet from a kyanite-eclogite
10	Obidim eclogite, Bansko Municipality, Blagoevgrad Province, Bulgaria	Janák, M.; Froitzheim, N.; Georgiev, N.; Nagel, T. J.; Sarov, S. (2011) P-T evolution of kyanite eclogite from the Pirin Mountains (SW Bulgaria): implications for the Rhodope UHP Metamorphic Complex. Journal of Metamorphic Geology, 29 (3). 317-332 doi:10.1111/j.1525-1314.2010.00920.x	EMPA analysis ( State Geological Institute of Dionyz Stur in Bratislava).of a matrix ambibole from a kyanite-eclogite
11	Red Hill, Moultonborough, Carroll County, New Hampshire, USA	DORAIS, M. J., & FLOSS, C. (1992). An ion and electron microprobe study of the mineralogy of enclaves and host syenites of the Red Hill Complex, New Hampshire, USA. Journal of Petrology, 33(5), 1193-1218.	Sample from a silica saturated syenite
12	Lục Yên District, Yên Bái Province, Vietnam	Garnier, V., Ohnenstetter, D., Giuliani, G., Maluski, H., Deloule, E., Trong, T. P., Pham Van, L., Hoang Quang, V. (2005) Age and significance of ruby-bearing marble from the Red River Shear Zone, northern Vietnam. The Canadian Mineralogist, 43 (4). 1315-1329 doi:10.2113/gscanmin.43.4.1315
13	Kovalo eclogites, Kechros, Arriana, Rhodope, Eastern Macedonia and Thrace, Greece	Mposkos, E.; Baziotis, I.; Proyer, A. (2011) Pressure–temperature evolution of eclogites from the Kechros complex in the Eastern Rhodope (NE Greece). International Journal of Earth Sciences, 101 (4). 973-996 doi:10.1007/s00531-011-0699-2	EMPA analysis from an amphibole from a retrogressed eclogite. The amphibole is from a symplectitic intergrowth with plagioclase after omphacite.

Crystallography of Hornblende Root Name GroupHide

Crystal System:

Monoclinic

Crystal StructureHide

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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)
0012672	Ferro-hornblende	Guha R, Nag D K, Iyengar S V P (1987) Structure of an amphibole from Simlipal granite, India Indian Minerals 41 32-41	1987	Simlipal granite, India	0	293

CIF Raw Data - click here to close

Relationship of Hornblende Root Name Group to other SpeciesHide

Member of:

Calcium Amphibole Subgroup > w(OH,F,Cl)-dominant Amphibole Group > Amphibole Supergroup

Other Members of Calcium Amphibole Subgroup:

Actinolite Root Name Group	◻Ca₂(Mg_0-4.5M²⁺_0.5-5)Si₈O₂₂(OH,F,Cl)₂
Cannilloite Root Name Group	CaCa₂(Z²⁺₄Z³⁺)(Si₅Al₃O₂₂)(OH,F,Cl)₂
Edenite Root Name Group	ACa₂Z₅(AlSi₇O₂₂)((OH),F,Cl)₂	Mon.
Hastingsite Root Name Group	ACa₂(Z²⁺₄Fe³⁺)(Al₂Si₆O₂₂)(OH,F,Cl)₂
Joesmithite	Pb²⁺Ca₂(Mg₃Fe³⁺₂)(Si₆Be₂)O₂₂(OH)₂	Mon. 2/m : P2/b
Pargasite Root Name Group	(A)(Ca₂){Z²⁺₄Z³⁺)(Al₂Si₆O₂₂)(OH,F,Cl)₂
Sadanagaite Root Name Group	A (Ca₂)(Z²⁺₃Z³⁺₂)(Si₅Al₃O₂₂)(OH,F,Cl)₂	Mon.
Tremolite Root Name Group	◻Ca₂(Mg_4.5-5M²⁺_0-0.5)Si₈O₂₂W₂
Tschermakite Root Name Group	◻(Ca₂)(Z²⁺₃Z³⁺₂}(Al₂Si₆O₂₂)(OH,F,Cl)₂

Hornblende Root Name Group Members:

Ferro-ferri-hornblende	◻Ca₂(Fe²⁺₄Fe³⁺)(AlSi₇O₂₂)(OH)₂	Mon. 2/m : B2/m
Ferro-hornblende	◻Ca₂(Fe²⁺₄Al)(Si₇Al)O₂₂(OH)₂	Mon. 2/m : B2/m
Magnesio-ferri-fluoro-hornblende	◻Ca₂(Mg₄Fe³⁺)(AlSi₇O₂₂)F₂	Mon. 2/m : B2/m
Magnesio-ferri-hornblende	◻Ca₂(Mg₄Fe³⁺)[(Si₇Al)O₂₂](OH)₂	Mon. 2/m : B2/m
'Magnesio-fluoro-hornblende'	◻Ca₂(Mg₄Al)(AlSi₇O₂₂)F₂
Magnesio-hornblende	◻Ca₂(Mg₄Al)(Si₇Al)O₂₂(OH)₂	Mon. 2/m : B2/m

Chemically related to group(s):

Tschermakite Root Name Group

◻(Ca₂)(Z²⁺₃Z³⁺₂}(Al₂Si₆O₂₂)(OH,F,Cl)₂

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 Hornblende Root Name GroupHide

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References for Hornblende Root Name GroupHide

Reference List:

Hawthorne, F. C., Oberti, R., Harlow, G. E., Maresch, W. V., Martin, R. F., Schumacher, J. C., Welch, M. D. (2012) Nomenclature of the amphibole supergroup. American Mineralogist, 97 (11) 2031-2048 doi:10.2138/am.2012.4276

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