Bradley (1994) has suggested that grains known as GEMS (glass with embedded metal and sulphides) found in interplanetary dust particles are interstellar silicate grains. Understanding GEMS would then hold promise of fresh insight into diverse problems concerning interstellar grains, such as their origin and processing in the interstellar medium, differential depletion of the elements, grain alignment, the effective dielectric function of dirty silicates, and the infrared spectra of amorphous silicates. On the other hand, astronomical constraints might ultimately rule out this hypothesis.