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tokens: to calculate the percentage retention of Si and C by the mantle. Upon simulating the sputtering yield for two cases, one with a 0.02 μ m thick ice mantle and another without an ice mantle, we observe a higher number of recoils in the grain with an ice mantle. This shows that having an ice mantle accelerates the sputtering process and increases the collision cascade inside the grain. Due to the limitations of using Monte Carlo simulations, it is hard to arrive at the exact change in collision cascade due to the ice mantle. Nonetheless, the central point of this result is to emphasize the destructive nature of the ice mantle along with its protective nature when it retains the ejected atoms from the core. This increase might not affect the absolute value of sputtering; however, it makes the grain more amorphous. Also, for relatively slow-moving projectiles such as shock-wave-accelerated particles, there would be even higher amorphization. Most of the presolar SiC grains analyzed in the laboratory have been reported to be crystalline and even spectroscopically detected as a 11 μ m feature. The absence of amorphous SiC in both the laboratory and spectroscopically has been under discussion for the past two decades, mainly because the majority of presolar silicate grains studied in the laboratory have amorphous structure (Vollmer et al. 2009 ). Both amorphous and crystalline (10%) silicates have been observed around AGB stars and young main-sequence stars (Demyk et al. 2000 ). To understand the grain shape and size dependence on infrared spectra, Speck et al. ( 2005 ) compared IR spectra from various polytypes of SiC in the laboratory. This study indicated the possibility of a 9 μ m feature being related to amorphous SiC. As for the laboratory measurements, this difference between presolar silicates and SiC mainly arises due to the different identification/separation methods. Presolar silicates have been identified based on in situ measurement, whereas SiCs are chemically separated. The in situ measurements within the meteorite sections have much less of an effect on the morphology of the grains, and hence the amorphous grains remain unaltered/intact. On the other hand, harsh chemicals used in chemical separation method could lead to the destruction of presolar grains, especially amorphous grains (disordered structure) in comparison to crystalline ones (ordered crystals). Limited efforts have been put into an in situ search of SiC within meteorite sections, and no morphological studies exist for them as of yet. Nonetheless, simulation in the present study indicates amorphization of ice-mantle SiC through GCR interactions, and hunting for these amorphous grains through in situ searches in future would be desirable. As the ice thickness or the density increases, the GCR loses more energy and increases the capacity of destruction. Introduction of Si and C from the core in this ice mantle may also increase the density of the ice mantle; however, this