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Northwest Africa 6998
Basic information Name: Northwest Africa 6998
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6998
Observed fall: No
Year found: 2004
Country: (Northwest Africa)
Mass:help 85.3 g
Meteoritical Bulletin:  MB 101  (2012)  H4
Recommended:  H4    [explanation]

This is 1 of 6400 approved meteorites (plus 2 unapproved names) classified as H4.   [show all]
Search for other: H chondrites, H chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 7 Jul 2012
Writeup from MB 101:

Northwest Africa 6998 (NWA 6998)

(Northwest Africa)

Purchased: 2004

Classification: Ordinary chondrite (H4)

History: The specimen was loaned to the Royal Ontario Museum in 2002.

Physical characteristics: Dark, 85.34 g, partially fusion crusted stone, with patches of rusty brown iron staining. Weathering has exposed a melt vein to the surface. Clasts of a darker color are also visible.

Petrography: (V. Di Cecco, ROM) Chondrules well defined and comprise 66.5% of the sample. Matrix contains opaques and chondrule fragments. Chondrules 0.21 to 1.125 mm in diameter with an average size of 0.61 mm. Olivine dominates the sample as well as orthopyroxene. Clinopyroxene is less abundant along with kamacite. Plagioclase is often present in porphyritic chondrules. Troilite is present in lower abundances.

Geochemistry: (V. Di Cecco, ROM) Olivine, Fa16.8±5.6 (n=26); low-Ca pyroxene, Fs15.6±0.4Wo2.9±0.8 (n=6); high-Ca pyroxene, Fs17.6±3.7Wo10.5±6.1 (n=7).

Classification: (V. Di Cecco, ROM) Ordinary Chondrite (H4, S3, W2)

Specimens: One specimen exists with a total mass of 85.39 g, which has been cut into five pieces. The largest of these pieces weighs 73.60 g. All specimens are at ROM.

Data from:
  Table 0
  Line 0:
Place of purchase:Tucson
Date:P 2004
Mass (g):85.34
Shock stage:S3
Weathering grade:W2
Fayalite (mol%):16.8±5.6 (n=26)
Ferrosilite (mol%):15.6±0.4 (n=6); 17.6±3.7 (n=7)
Wollastonite (mol%):2.9±0.8 (n=6); 10.5±6.1 (n=7)
Classifier:V. Di Cecco, ROM
Type spec mass (g):85.34
Type spec location:ROM
Main mass:ROM
Comments:Submitted by Kim Tait
   and collections
ROM: Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada (institutional address; updated 18 Oct 2011)
References: Published in Meteoritical Bulletin, no. 101, MAPS 50, 1661, September 2015
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     This is 1 of 8904 approved meteorites from (Northwest Africa) (plus 1871 unapproved names)

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