Five SiC fractions were isolated from the Murray and Murchison C2 chondrites, and were examined by noble-gas and ion-probe mass spectrometry as well as by SEM-EDX. The SiC (totalling ~6–9 ppm of the meteorites) contains record concentrations of the exotic components Ne-E(H) (nearly monoisotopic Ne 22) and Xe-S (enriched in isotopes 128, 130, 132), which are located in coarse- and finegrained SiC, respectively. The Ne 21-content exceeds up to 40-fold that expected from the recent cosmicray irradiation, implying a presolar cosmic-ray exposure age of 39 (+19, −13) Ma. This age is much shorter than the predicted ~500 Ma lifetime of refractory interstellar grains and implies one of the following: a selective interstellar destruction process for SiC, enhanced supernova activity in the protosolar neighborhood, or late outgassing of >90% of the SiC. Si, C, and N all have highly anomalous and variable isotopic compositions, varying by 1.4×, 16×, and 120×. Analysis of 12 single, mainly monocrystalline grains (which must be endmembers) shows that at least 4 and probably ≥6 independent Si components are present, corresponding to a like number of individual stars. As SiC is stable only at C O ≥ 0.83 (nearly 2× solar), its parent stars must be mainly carbon-rich red giants. The mean C 12 C 13 ratio of SiC indeed resembles that of present-day carbon stars and interstellar gas (44 ± 3 vs. 45 ± 4 and 43 ± 4), but in view of the ~4.6 × 10 9 y difference in age, this agreement is surprising. Correlations between C 12 C 13 and N 14 N 15 show mainly the signature of hydrostatic H-burning followed by early stages of He-burning (red giants), less commonly explosive H-burning (novae) or advanced stages of He-burning (Wolf-Rayet stars, Type II supernovae). The first two stellar types could also account for Xe-S and Ne-E, respectively. Meteorites contain only 4 × 10 −5 of their Si as SiC, in contrast to an estimated value of ~1 3 for fresh interstellar matter. Some selective destruction process is required, either in interstellar space or in the early solar system.