NWA 11304 R4 Chondrite - 136g Individual
Available in this listing is a spectacular 136 gram R4 individual specimen of the "R" Chondrite class of meteorites. This is a very rare type, and this individual has remnant fusion crust, thumbprinting, visible exterior chondrules, and lithic lasts clearly visible, which could also contain R3 material. With the contrasting visible clasts (light and dark), this is a collector's piece ready to show out of the box.
Petrography: (A. Irving and S. Kuehner, UWS) The specimen is a breccia mostly composed of well-formed, relatively small chondrules (apparent diameter 250±150 µm, N = 12) in a finer grained matrix (~30 vol.%), but some petrologically-similar, angular lithic clasts (including type 3 and type 4 clasts) are also present. Both olivine and orthopyroxene have very magnesian cores, but the predominant mafic minerals are much more ferroan. Other minerals are clinopyroxene, sodic plagioclase, pentlandite, pyrrhotite and magnetite.
Geochemistry: Olivine (cores Fa1.0-1.2; predominantly Fa39.1-41.6; N = 4), orthopyroxene (core Fs4.5Wo0.4; mantle Fs16.3Wo2.7), clinopyroxene (Fs11.0-12.4Wo45.5-41.7, N = 2), plagioclase (Ab85.7An12.3Or14.6).
Classification: R4. May contain R3 material.