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Eas a Bradain, Luib, Isle of Skye, North West Highlands (Inverness-shire), Scotland, UK
© Steve Rust
|Calcium Amphibole Subgroup > w(OH, F, Cl)-dominant Amphibole Group > Amphibole Supergroup|
|Name:||Defined in the 2012 amphibole nomenclature|
The group is defined 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 it's 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 magnesio-hornblende group is an IMA-CNMNC defined amphibole root-name group 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 undefined amphibole in the calcium ( and sometimes in the sodium-calcium) subgroups.
Classification of Magnesio-hornblende group
|IMA status:||Approved 2012|
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Chemical Properties of Magnesio-hornblende group
|Simplified for copy/paste:||☐(Ca2)(Z2+4Z3+}(AlSi7O22)(OH,F,Cl)2|
Relationship of Magnesio-hornblende group to other Species
|Member of:||Calcium Amphibole Subgroup > w(OH, F, Cl)-dominant Amphibole Group > Amphibole Supergroup|
|Other Members of Group:|
|Chemically related to group(s):|
|Health Warning:||No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.|
References for Magnesio-hornblende group
Frank C. Hawthorne, Roberta Oberti, George E. Harlow, Walter V. Maresch, Robert F. Martin, John C. Schumacer, Mark D. Welch (2012): Nomenclature of the amphibole supergroup, American Mineralogist, Volume 97, pages 2031–2048
Best Localities for Magnesio-hornblende group
|Best of Species:||Magnesio-hornblende group|
Internet Links for Magnesio-hornblende group
Localities for Magnesio-hornblende group
The 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.