Keilite Explained

Keilite
Category:	Sulfides
Imasymbol:	Ke^[1]
Molweight:	81.91 gm
Strunz:	2/C.15-15
Dana:	2.8.1.9
System:	Isometric
Class:	Hexoctahedral
Symmetry:	Fmm (No. 225)
Unit Cell:	a = 5.1717(18)Å
Colour:	Grey
Habit:	Microscopic crystals
Cleavage:	Distinct/good
Tenacity:	Brittle
Luster:	Metallic
Diaphaneity:	Opaque
Gravity:	3.958
Density:	3.958

Keilite is an iron-magnesium sulfide mineral with the chemical formula that is found in enstatite chondrites.^[2] Keilite is the iron-dominant analog of niningerite.^{[3] [4]} Keilite is named after Klaus Keil (born 1934).

Occurrences

Examples of keilite occurrences are enstatite chondrites and the Zakłodzie meteorite. It appears to be confined to impact-melt influenced enstatite chondrites that were quenched. There are also some meteorites interpreted as impact-melt breccias that do not contain keilite. This is explained as a deeper burial after impact, which slowed cooling and enabled retrograde reactions (diapthoresis) to take place.^[5]

Notes and References

1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
2. Web site: Keilite Mineral Data. 15 February 2021. WebMineral.
3. Web site: Keilite. dead. https://web.archive.org/web/20160303171359/http://www.handbookofmineralogy.com/pdfs/keilite.pdf. 3 March 2016. 15 February 2021. Handbook of Mineralogy.
4. Shimizu M, Yoshida H, Mandarino JA. The New Mineral Species Keilite, (Fe,Mg)S, The Iron-Dominant Analogue of Niningerite. The Canadian Mineralogist. 2002. 40. 6. 1687–1692. 10.2113/gscanmin.40.6.1687. 93381076 .
5. Keil. Klaus. Occurrence and origin of keilite, (Fe>0.5,Mg<0.5)S, in enstatite chondrite impact-melt rocks and impact-melt breccias. Chemie der Erde - Geochemistry. 30 April 2007. 67. 1. 37–54. 10.1016/j.chemer.2006.05.002. 2007ChEG...67...37K.