Fine-grained assemblages of majorite and glassy grains are for the first time identified in a shock-induced melt vein in an H chondritic meteorite. The bulk chemical composition of these aggregates is similar to that of diopside CaMgSi 2 O 6 in the host rock. Both majorite and glassy grains are Ca-rich and their formulae can be approximated as (Mg 0 . 6 5 Fe 0 . 0 9 Ca 0 . 2 6 )SiO 3 and (Mg 0 . 2 3 Fe 0 . 0 5 Ca 0 . 7 2 )SiO 3 , respectively. These Ca-rich assemblages are dissociation products of the host diopside and were produced at ~18-24 GPa by a shock event. The CaSiO 3 -rich glass is inferred to have crystallized in a perovskite structure, but was vitrified during the pressure release.