The SEM-EDS spectrum of an inner particle shows a Mg-based mineral. The carbon observed here is probably from the encapsulating coating. The same spectra were obtained from two other particles; e) A SEM-EDS spectrum of the outer part. The prevailing element is carbon, with some oxygen. The chemical content and the circular form of the particle support the suggestion that the covering material is of organic nature.
[From the group of Yinon Rudich]
