Fig. 1: Backscattered electron images (BSE) and element maps of sub-spherical objects (SSO) in Ryugu.

Element maps have been chosen to illustrate the properties of the sulphide rims and the differences between the interior and surrounding matrix. a SSO C-01 decorated with euhedral sulphides; Element maps of chondrule C-01 showing (b) S, c Ni, d Si and e Mg; f High magnification image showing the homogeneous silicate core of C-01, sulphides and surrounding matrix; g SSO C-02 showing a sulphide rim surrounding a silicate-dominated core with a texture similar to surrounding matrix; Element maps of C-02 showing (h) S, i Fe, j Ni, k Si; l A high magnification BSE image of the rim of C-02 showing polycrystalline subhedral sulphide crystals; m SSO C-03 showing a sub-spherical core surrounded by fractures decorated with three small Ni-bearing sulphides; Element maps of C-03 showing (n) S, o Ni, p Mg, q Na; r A high magnification BSE image of C-03 showing the textural difference between the core (right) and the surrounding matrix (left); s SSO C-41 showing a homogeneous silicate core with veins of sub-micron iron oxides. The SSO is surrounded by a rim of euhedral sulphide. The object is fractured; t SSO C-44 exhibits a core with a facetted anhydrous silicate crystals set in a cryptocrystalline matrix (CC) consisting of phyllosilicate; u Two SSOs (C-20/21) with homogeneous silicate cores and sulphide rims. Abbrev: Sul—sulphide, C—core, Fr—fracture, V—vein, P—phenocryst-like phases.