Fig. 1: Modified magnetite and iron sulfides on a Ryugu grain.

a, Backscattered electron image of a fine Ryugu grain. The white boxes correspond to the areas shown in b and c. b, Secondary electron image of framboidal magnetite showing granular texture. c, Secondary electron image of porous iron sulfide surrounded by phyllosilicate. The arrow points to an iron whisker on the iron sulfide surface. Sample ID is A0104-021012.