Chemistry:Ixiolite
| Ixiolite | |
|---|---|
 Ixiolite found in Mozambique | |
| General | |
| Category | Oxide minerals |
| Formula (repeating unit) | (Ta,Nb,Sn,Mn,Fe) 4O 8[1] or (Ta,Mn,Nb)O 2[2] |
| Strunz classification | 4.DB.25 |
| Crystal system | Orthorhombic, some varieties might be monoclinic[3][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 |
| |re|er}} | Sub-metallic |
| Diaphaneity | Opaque |
| Specific gravity | 7.03 - 7.23 |
| References | [1][4][5][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)
4O
8 or (Ta,Mn,Nb)O
2.
Structure
Ixiolite was originally reported as crystallizing in the monoclinic crystal system.[4] Detailed studies of the scandium, tin and titanium rich varieties indicate that they form crystals in the orthorhombic system whereas tungsten ixiolite is monoclinic.[3]
Discovery and occurrence
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.[4]
Substitution and varieties
Trace elements include zirconium, hafnium, titanium and tungsten.[4]
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.[3]
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.[3]
Economic importance
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
- "The Tanco pegmatite at Bernic Lake, Manitoba. II. Wodginite, tantalite, pseudo-ixiolite and related minerals". The Canadian Mineralogist 11: 609–642. 1972. http://rruff.info/rruff_1.0/uploads/CM11_609.pdf.
- "The crystal structures of tantalite, ixiolite and wodginite from Bernic Lake, Manitoba I. Tantalite and ixiolite". The Canadian Mineralogist 14: 540–549. 1976. http://rruff.info/rruff_1.0/uploads/CM14_540.pdf.
- The crystal structures of tantalite, ixiolite and wodginite from Bernic Lake, Manitoba; II, Wodginite
References
- ↑ 1.0 1.1 1.2 1.3 Mindat.org - Ixiolite
- ↑ 2.0 2.1 2.2 2.3 https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Ixiolite Mineralienatlas
- ↑ 3.0 3.1 3.2 3.3 Wise, M.A.; Černý, P.; Falster, A.U. (1998). "Scandium substitution in columbite-group minerals and ixiolite". Canadian Mineralogist 36: 673–680. http://rruff.info/rruff_1.0/uploads/CM36_673.pdf.
- ↑ 4.0 4.1 4.2 4.3 "Ixiolite". Handbook of Mineralogy. Mineralogical Society of America. http://www.handbookofmineralogy.com/pdfs/ixiolite.pdf.
- ↑ Ixiolite data on Webmineral
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ "Niobium-Tantalum". bgs.ac.uk. http://www.bgs.ac.uk/downloads/start.cfm?id=2033.
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