In the interstellar space it is subjected to the action of high energy rays. It is assumed that this will lead to amorphization of the material. This is also true for silicates. Olivine and pyroxene are the dominant silicates with olivine having a larger mass fraction than orthopyroxene. In the warmer regions of accretions diskas as well as in the warmer regions of molecular cloud cores, some or all of the grain spezies are chemically transfomed or sublimate.
Silicates change into the crystalline state due to the effect of thermally annealing .
Spiraling inward towards the protostar the grain spezies start to vaporize. Only a small fraction of the Mg and Si is involved in this part of the condensation sequence. Possibly the excess SiO converts forsterite into enstatite. Furthermore, the chaotically condensed silicates might be subdued to thermally annealing to transform into the crystalline state. Finally, dust condensed in stellar atmospheres becomes part of the interstellar medium.