THERE is a fairly general consensus of opinion that the interstellar dust consists basically of graphite, with or without various coatings on the grains. In proposing this constitution, Hoyle and Wickramasinghe1 suggested that the grains could be formed in the atmospheres of cool giant stars, in particular the N-type carbon stars. The same authors2 later proposed that grains can also be formed in the explosion of super-massive objects, such as the nuclei of Seyfert galaxies. This has been extended more recently by Reddish and Wickramasinghe3 to include the explosions of supernovae.