Y-791439, 51-2: Diogenite

(cumulate eucrite  breccia with minor diogenitic and eucritic components)

          Y-791439 is texturally similar to Y-75032, but it contains more abundant clasts of cumulate eucrite than does Y-75032; six clasts (to 2.8 x 2.3 mm) are observed in the PTS. Pyroxene chemical compositions of Y-791439 are divided into four types: D, B, MC, JV. The D-type pyroxenes are the most magnesian in the meteorite, and are similar to Fe-rich diogenites. The B-type pyroxenes are the most abundant, and many of them preserve the original lithic clast shape. The chemical compositions of B-type pyroxenes are slightly more Fe-rich than Binda, but many of them have blebs typical of the Binda cumulate eucrite. The MC-type and JV-type pyroxenes are severely brecciated. The chemical compositions of MC-type are close to those of Moore County and those of rare JV to Juvinas. Minor plagioclase grains are present in the matrix. Y-791439 is classified as an unusual howardite rich in cumulate eucrite components with minor diogenite and rare ordinary eucrite components.