Ixiolite
| Ixiolite | |
|---|---|
 Ixiolite found in Mozambique | |
| General | |
| Category | Oxide minerals |
| Formula (repeating unit) | (Ta,Nb,Sn,Mn,Fe)4O8[1] or (Ta,Mn,Nb)O2[2] |
| IMA symbol | Ix[3] |
| Strunz classification | 4.DB.25 |
| Crystal system | Orthorhombic, some varieties might be monoclinic[4][1] |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Pbcn[2] |
| Unit cell | a = 4.785, b = 5.758 c = 5.16 [Å]; Z = 4[2] |
| Identification | |
| Color | Steel-grey, black |
| Crystal habit | Irregular granular or inclusions, also as prismatic crystals; some varieties might be pseudoorthorhombic |
| Twinning | Uncommon on {013} |
| Fracture | Irregular/ uneven, sub-conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 6 - 6+1⁄2 |
| Luster | Sub-metallic |
| Diaphaneity | Opaque |
| Specific gravity | 7.03 - 7.23 |
| References | [1][5][6][2] |
Ixiolite is an accessory oxide mineral found in granitic pegmatites. It is an oxide with the general chemical formula (Ta,Nb,Sn,Mn,Fe)4O8 or (Ta,Mn,Nb)O2.
Structure
[edit]Ixiolite was originally reported as crystallizing in the monoclinic crystal system.[5] Detailed studies of the scandium, tin and titanium rich varieties indicate that they form crystals in the orthorhombic system whereas tungsten ixiolite is monoclinic.[4]
Discovery and occurrence
[edit]It was first described in 1857 for an occurrence at Skogsböle, Kimito Island, Finland. The name is for Ixion, the Greek mythological character related to Tantalus, as the mineral contains tantalum.[1]
Ixiolite is typically associated with feldspar, tapiolite, cassiterite, microlite, and rutile.[5]
Substitution and varieties
[edit]Trace elements include zirconium, hafnium, titanium and tungsten.[5]
As with other tantalum and niobium bearing minerals considerable substitution and a number of varieties exist. Substitutions in the formula are common and the varieties stannian ixiolite (tin), titanian ixiolite (titanium) and wolframian ixiolite (tungsten) have been reported.[4]
Scandium is present in many ixiolite sample with percentages up to 4.0 percent Sc2O3, but usually less than one percent scandium oxide. High scandium ixiolites, containing from 4 to 19% scandium oxide are typically also rich in tin and titanium.[4]
Economic importance
[edit]Ixiolite together with microlite, tantalite, tapiolite, wodginite are the most important minerals mined for the element tantalum. Ixiolite contains about 69 % tantalum oxide (Ta2O5) and is a common constituent of coltan ore.[7]
Further reading
[edit]- Grice JD, Černý P, Ferguson RB (1972). "The Tanco pegmatite at Bernic Lake, Manitoba. II. Wodginite, tantalite, pseudo-ixiolite and related minerals" (PDF). The Canadian Mineralogist. 11: 609–642.
- Grice JD, Ferguson RB, Hawthorne FC (1976). "The crystal structures of tantalite, ixiolite and wodginite from Bernic Lake, Manitoba I. Tantalite and ixiolite" (PDF). The Canadian Mineralogist. 14: 540–549.
- The crystal structures of tantalite, ixiolite and wodginite from Bernic Lake, Manitoba; II, Wodginite
References
[edit]- ^ a b c d Mindat.org - Ixiolite
- ^ a b c d https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Ixiolite Mineralienatlas
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b c d Wise, M.A.; Černý, P.; Falster, A.U. (1998). "Scandium substitution in columbite-group minerals and ixiolite" (PDF). Canadian Mineralogist. 36: 673–680.
- ^ a b c d "Ixiolite" (PDF). Handbook of Mineralogy. Mineralogical Society of America. Archived from the original (PDF) on 10 October 2012. Retrieved 20 February 2013.
- ^ Ixiolite data on Webmineral
- ^ "Niobium-Tantalum". bgs.ac.uk. Retrieved 2 March 2013.