Chondrules relict grains

Compound chondrules, relict grains, and chondrule rims... 

From the abundances of igneous rims, compound chondrules, and relict grains and the dearth of unmelted, chondrule-sized dustballs, we infer that collisions between partly melted objects and remelting of aggregates from such collisions were important processes that enabled chondrules to form from fine particles. 

Figure 22 Combined elemental map in magnesium (red), calcium (green), and A1 K (blue) X-rays ((a), (b)) and backscattered electron images ((b), (d)) of two barred or skeletal olivine chondrules, and a combined X-ray map (e) and NiKa scanning map (f) of a zoned Fe,Ni metal grain with an enclosed cryptocrystalline chondrule (CC) in the CBb chondrite HaH 237 (Krot et al, 2002a). The chondrules, which contain forsteritic olivine (ol), low-calcium pyroxene (px), high-calcium pyroxene (cpx) and mesostasis (mes), lack rims and relict grains and clearly formed in a dust-free environment from total melts (reproduced by permission of University of Arizona on behalf of The Meteoritical...

Jones R. H. (1996b) Relict grains in chondrules evidence for chondrules recycling. In Chondrules and the Protoplanetary Disk (eds. R. H. Hewins, R. H. Jones, and E. R. D. Scott). Cambridge University Press, Cambridge, pp. 163-172. 

Wasson J. T. and Rubin A. E. (2003) Ubiquitious low-FeO relict grains in type 11 chondrules and limited overgrowths on phenocrysts following the final melting events. Geochim. Cosmochim. Acta 67, 2239—2250. 

The precise nature of the chondrule-form-ing event, the "chondrule factory," is also the subject of some discussion. Some workers favor the formation of chondrules by the direct condensation of the solar nebula gas as a melt. Alternatively, chondrules could be the residues of evaporation. The presence of relict olivine grains in some chondrules (Jones, 1996) argues against a simple condensation model and may imply multiple condensation-evaporation events. 

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