Arfvedsonite
Sodium amphibole mineral
title: "Arfvedsonite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["amphibole-group", "sodium-minerals", "iron(ii,iii)-minerals", "magnesium-minerals", "monoclinic-minerals", "blendes", "minerals-in-space-group-12", "minerals-described-in-1823"] description: "Sodium amphibole mineral" topic_path: "general/amphibole-group" source: "https://en.wikipedia.org/wiki/Arfvedsonite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Sodium amphibole mineral ::
::data[format=table title="Infobox mineral"]
| Field | Value |
|---|---|
| name | Arfvedsonite |
| category | Inosilicates |
| Amphiboles | |
| image | Arfvedsonit-167989.jpg |
| imagesize | 260px |
| formula | [Na][Na2][(Fe2+)4Fe3+][(OH)2 |
| IMAsymbol | Arf |
| strunz | 9.DE.25 (10 ed) |
| VIII/F.08-100 (8 ed) | |
| dana | 66.1.3c.9 |
| system | Monoclinic |
| class | Prismatic (2/m) |
| (same H-M symbol) | |
| symmetry | C2/m |
| color | Black, deep green on thin edges |
| habit | Fibrous, radial prismatic aggregates |
| twinning | Simple or lamellar parallel to [100] |
| cleavage | Perfect on [110] |
| fracture | Uneven |
| tenacity | Brittle |
| mohs | 5–6 |
| luster | Vitreous |
| streak | Deep bluish gray, gray-green |
| diaphaneity | Translucent to opaque |
| gravity | 3.3–3.5 |
| opticalprop | Biaxial (−) |
| refractive | nα = 1.652–1.699 |
| nβ = 1.660–1.705 | |
| nγ = 1.666–1.708 | |
| birefringence | δ = 0.014 |
| pleochroism | Strong: Blue-greens, yellow-browns, gray-violets |
| dispersion | r v strong |
| references | |
| :: |
| name = Arfvedsonite | category = Inosilicates Amphiboles | image = Arfvedsonit-167989.jpg | imagesize = 260px | alt = | caption = | formula = [Na][Na2][(Fe2+)4Fe3+][(OH)2|Si8O22] |IMAsymbol=Arf | molweight = | strunz = 9.DE.25 (10 ed) VIII/F.08-100 (8 ed) | dana = 66.1.3c.9 | system = Monoclinic | class = Prismatic (2/m) (same H-M symbol) | symmetry = C2/m | color = Black, deep green on thin edges | colour = | habit = Fibrous, radial prismatic aggregates | twinning = Simple or lamellar parallel to [100] | cleavage = Perfect on [110] | fracture = Uneven | tenacity = Brittle | mohs = 5–6 | luster = Vitreous | streak = Deep bluish gray, gray-green | diaphaneity = Translucent to opaque | gravity = 3.3–3.5 | density = | polish = | opticalprop = Biaxial (−) | refractive = nα = 1.652–1.699 nβ = 1.660–1.705 nγ = 1.666–1.708 | birefringence = δ = 0.014 | pleochroism = Strong: Blue-greens, yellow-browns, gray-violets | 2V = | dispersion = r v strong | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references =
Arfvedsonite () or soda hornblende (partiellement obsolète) is a sodium amphibole mineral with composition: [Na][Na2][(Fe2+)4Fe3+][(OH)2|Si8O22]. It crystallizes in the monoclinic prismatic crystal system and typically occurs as greenish black to bluish grey fibrous to radiating or stellate prisms.
It is a rather rare mineral occurring in nepheline syenite intrusions and agpaitic (peralkaline) pegmatites and granites as the Golden Horn batholith in Okanogan County, Washington (type locality for zektzerite). Occurrences include Mont Saint-Hilaire, Quebec, Canada; the Ilímaussaq complex in Southern Greenland; and in pegmatites of the Kola Peninsula, Russia. Its mineral association includes nepheline, albite, aegirine, riebeckite, katophorite and quartz.
Arfvedsonite was discovered in 1823 and named for the Swedish chemist Johan August Arfwedson (1792–1841).
References
- Deer, W.A., R.A. Howie, and J. Zussman (1963) Rock-forming Minerals, v. 2, Chain Silicates, p. 364–374
- Mineral Galleries
References
- Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
- [http://rruff.geo.arizona.edu/doclib/hom/arfvedsonite.pdf Arfvedsonite]. Handbook of Mineralogy
- [http://www.mindat.org/min-325.html Arfvedsonite]. Mindat.org
- [http://webmineral.com/data/Arfvedsonite.shtml Arfvedsonite]. Webmineral
- "IMA Master List".
- (2003). "The Chambers Dictionary". Chambers.
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