Carbonaceous chondrite (CV3)
Found, 2011; 0.1 g

After 1.5 tons of clay were panned and tiny pieces of a chondrite (7 grains) were found during an expedition to Chukotka in far eastern Russia by scientists from the US, Russia and Italy from July 20 to August 7, 2011. They were in search of icosahedrite which had been discovered there recently. An additional three grains from an earlier 1979 expedition were also later identified as fragments from the same CV3 carbonaceous chondrite. The grains [~1 or < 1 mm in max. dimension] are dark grey with visible silicates and metal. SEM observations of two grains revealed zoned porphyritic chondrules [PO] with forsteritic cores as well as enstatite [sensu strictu] rimmed by Fe-rich olivine. The matrix is porous with composition and minerals (awaruite, diopside, nepheline, pentlandite, CAI spinel, etc.) typical of CV3 (Vigarano-like) chondrites. Very small amounts of localized hematite are present, but most of the meteoritic material is — at most — mildly altered by terrestrial weathering. However, the most remarkable discoveries have been those of new Al-rich minerals and the first recognized natural quasi-crystals.

We note here only the most remarkable of these findings as they are expected to be outdated in the near future. By early January 2017, Khatyrka had become the type location for 8 new Al-rich minerals (listed below). Six of the new minerals have the expected symmetries for minerals (isometric [2], orthorhombic [2], monoclinic [1], tetragonal [1]). They include steinhardite, an aluminum dominated mineral, and hollisterite, a natural Al-Fe alloy. But the two other new minerals are quasicrystals. Icosahedrite was the 1st natural quasicrystal to be recognized (in 2010) as an IMA mineral. Decagonite, with 10-fold symmetry, has now been added to the list. Other mineral species from the meteorite are under review.

Other Regions, Features and Areas containing this locality

References