Hraschina meteorite, Zagreb County, Croatiai

Regional Level Types
Hraschina meteorite	Meteorite Fall Location
Zagreb County	County
Croatia	Country

Hraschina, Octahedrite (IID, Om)
Fall, 26 May 1751; 49 kg, 2 pieces

Very late in the afternoon a brilliant fireball, detonations, and other sounds were seen and heard over a large region as the Hraschina meteorite careened into the earth's atmosphere. Numerous witnesses reported that the fireball broke into two pieces and soon two fragments (39.7 and 9 kg) were recovered from two separate ~1 m pits just over a kilometer apart. The larger piece, marked by the regmaglypts and ablation pits of its atmospheric entry, was soon the object of scientific inquiry — including work by the metallurgist, Alois von Widmanstätten, and his associates. Upon etching of a polished section, the discovery of the interlaced lamellae of kamacite and taenite which we now call the Widmanstätten pattern was one of the results. This finding was a key step in differentiating meteoritic nickel-iron from the occasional terrestrial forms of metallic and oxidized iron which had confused the scientific intelligentsia of the 17th and 18th Centuries. The main mass (38 x 28 x 10 cm) is still largely unsectioned and has been preserved as a prime exemplar of an iron meteorite sculpted by its oriented atmospheric entry. The smaller mass, unfortunately, was sectioned by blacksmiths and has been lost to science.

The overall petrography, mineralogy, and geochemistry of Hraschina are — for an iron meteorite — somewhat nondescript. Abundant kamacite accompanied by taenite-and-plessite (~35 vol%) have been shocked (Neumann bands) and partially annealed before atmospheric entry. Schreibersite and lesser amounts of troilite are the primary accessory mineral phases. Daubréelite is also found. Wüstite and magnetite are found in the very thin, rapidly oxidized fusion crust.

Hraschina belongs to the small class of IIA irons which numbers only 22 members [early 2015]. Hraschina is itself one of only three witnessed IIA falls. The above summary, based primarily upon Buchwald's 1975 assay of then available samples, could be expanded. Further investigation with new nondestructive and/or micro-sampling techniques seems desirable. Nearly all of the larger mass (~39 kg) is at the Natural History Museum in Vienna, Austria.

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