Related by context. Frequent words. (Click for all words.) 59 igneous rock 58 zircons 58 kaolinite 58 quartz crystals 57 salt crystals 57 marine sediments 56 sedimentary rock 56 basaltic 56 clasts 56 spinel 56 corundum 55 snail shells 55 lunar soil 55 aragonite 54 spherules 54 ejecta 54 elemental composition 54 lavas 54 calcareous 54 basalt 54 loess 54 alternating layers 54 manganese oxide 54 olivine 53 apatite 53 MgO 53 silicates 53 nanosized 53 igneous 53 calcite 53 igneous rocks 53 micrometre 52 feldspar 52 silicate 52 siliceous 52 graphitic 52 isotopic composition 52 perovskite 51 metamorphic rocks 51 electron density 51 nanobubbles 51 iron oxides 51 boron nitride 51 magmas 51 colloid 51 waxy substance 51 protoplanetary disk 51 nacre 51 stromatolites 51 stalagmite 51 hydroxyapatite 51 continental crust 51 clastic 51 SiO 2 51 striations 51 Fig. 1A 50 molecularly 50 solar nebula 50 carbonaceous 50 vuggy silica 50 isotope ratios 50 oxide layer 50 eutectic 50 regolith 50 spheroid 50 tetrahedral 50 volcanic rock 50 microstructures 50 fluorescing 50 nanoclusters 50 monolayers 50 osmium 50 nanoporous 50 monazite 50 copper oxides 50 blebs 50 zeolites 50 diffraction pattern 50 ellipsoid 49 crystalline 49 mudstone 49 stalactite 49 X ray fluorescence 49 lava tubes 49 noble gases 49 superlens 49 electrochemically 49 pyroxenite 49 nanocrystalline 49 quartz 49 gneisses 49 monolayer 49 oceanic crust 49 isotopic 49 titanium oxide 49 chromophore 49 globule 49 surficial 49 calcrete 49 crystals 49 microfossils