X = emerald green, deep green; Y = grass-green, deep green, yellow; Z = brownish green, green, yellowish brown, yellow
2V angle
Measured: 60° to 90°, Calculated: 68° to 84°
Dispersion
moderate to strong r > v
References
[2][3][4][5]
Aegirine is a member of the clinopyroxene group of inosilicate minerals. It is the sodium endmember of the aegirine–augite series. It has the chemical formula NaFeSi2O6, in which the iron is present as the ion Fe3+. In the aegirine–augite series, the sodium is variably replaced by calcium with iron(II) and magnesium replacing the iron(III) to balance the charge. Aluminum also substitutes for the iron(III). Acmite is a fibrous green-colored variety.
Aegirine occurs as dark green monoclinic prismatic crystals. It has a glassy luster and perfect cleavage. Its Mohs hardness varies from 5 to 6 and its specific gravity is between 3.2 and 3.4.
Syenite with aegirine and acmite from Magnet Cove, Arkansas
This mineral commonly occurs in alkalic igneous rocks, nepheline syenites, carbonatites and pegmatites. It also appears in regionally
metamorphosed schists, gneisses, and iron formations; in blueschist facies rocks, and from sodium metasomatism in granulites. It may occur as an authigenic mineral in shales and marls. It occurs in association with potassic feldspar, nepheline, riebeckite, arfvedsonite, aenigmatite, astrophyllite, catapleiite, eudialyte, serandite and apophyllite.[2]
Localities include Mont Saint-Hilaire, Quebec, Canada; Kongsberg, Norway; Narsarssuk, Greenland; Kola Peninsula, Russia; Magnet Cove, Arkansas, US; Kenya; Scotland and Nigeria.
The acmite variety was first described in 1821, at Kongsberg, Norway,[6] and the aegirine variety in 1835 for an occurrence in Rundemyr, Øvre Eiker, Buskerud, Norway. Aegirine was named after Ægir, the Norse god of the sea.[3] A synonym for the mineral is acmite (from Greek ἀκμή "point, edge") in reference to the typical pointed crystals.[7]
Aegirine is a member of the clinopyroxene group of inosilicate minerals. It is the sodium endmember of the aegirine–augite series. It has the chemical...
The clinopyroxene is sodic whose composition varies from hedenbergite to aegirine-augite. This mineral eventually presents resorption shape. The reaction...
for a mechanism to make up the "missing" positive charge. In jadeite and aegirine this is added by the inclusion of a +3 cation (aluminium and iron(III)...
of the mineral. The black spots on some specimens are either augite or aegirine, the latter occurring in almost all charoites since they commonly grow...
characteristic dark color comes from its concentration of dark pyroxenes such as aegirine and augite. Blairmorite is an analcite-rich variety of phonolite. Nepheline...
Na2O + K2O > Al2O3, so that some of the alkali oxides must be present as aegirine or sodic amphibole rather than feldspar. The chemistry of volcanic rocks...
Peninsula, Russia. Its mineral association includes nepheline, albite, aegirine, riebeckite, katophorite and quartz. Arfvedsonite was discovered in 1823...
asbestiform variety crocidolite (blue asbestos). It occurs in association with aegirine, nepheline, albite, arfvedsonite in igneous rocks; with tremolite, ferro-actinolite...
Rim group, dated to 274,000–170,000 years ago Phonolite lava flows with aegirine phenocrysts, of the Inner Crater group, which represents the last volcanic...
have been used as gemstones. Such as: Actinolite Nephrite (var.) Adamite Aegirine Afghanite Agrellite Algodonite Alunite Amblygonite Analcime Anatase Andalusite...
(melanite) and aegirine. The abundance of melanite is very unusual in igneous rocks, though some syenites, leucitophyres, and aegirine-felsites resemble...
(1901–1948) for an occurrence on Iwagi Islet, Japan, where it is found in an aegirine syenite intrusive stock. It is found in a similar environment at Mont Saint-Hilaire...
named for Neptune, Roman god of the sea because of its association with aegirine from Àgir, the Scandinavian sea-god. The Gemological Institute of America...
astrophyllite is associated with feldspar, mica, titanite, zircon, nepheline, and aegirine. Common impurities include magnesium, aluminium, calcium, zirconium, niobium...
intrusives and in nepheline syenite pegmatites. It occurs associated with aegirine, sodalite, nepheline, neptunite, lamprophyllite, pectolite, serandite,...
characteristic of the phonolites may also be found in some trachytes; thus aegirine or aegirine augite forms outgrowths on diopside crystals, and riebeckite may...
commanded by Lt Cmdr Neil Foster RN. As well as collecting samples of the aegirine granite, "rockallite", for later analysis in London, the top of the rock...
much nepheline with hauyne or nosean. Their pyroxene is principally aegirine or aegirine-augite; some of them are rich in melanite. Microscopic sections of...
alkalic intrusive of Mont Saint-Hilaire, Quebec. It occurs associated with aegirine, microcline, albite, elpidite, epididymite, taeniolite, pectolite, calcite...
characteristically found in carbonatites. Associated minerals include zircon, aegirine, apatite, perovskite and columbite. It was first described in 1826 for...
associated with sugilite, albite and aegirine. Crystals are usually twinned. This mineral can be found in aegirine syenite. Warr, L.N. (2021). "IMA–CNMNC...
only in the most strongly peralkaline rocks. Mafic minerals may include aegirine, fayalite, aenigmatite, ilmenite, and sodic amphibole (often arfvedsonite...
in an aegerine-natrolite-microcline vein in foyaite, associated with aegirine, anatase, ancylite-(Ce), barylite, catapleiite, cerite-(Ce), cerite-(La)...
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