Related by context. Frequent words. (Click for all words.) 57 calcite 56 igneous rock 55 nacre 54 spherules 53 nanosized 53 calcareous 53 oceanic crust 53 clasts 52 salt crystals 52 otoliths 52 lunar soil 52 iron oxides 51 hollow tubes 51 stalactite 51 hydroxyapatite 51 chert 51 middens 51 surficial 51 ammonites 50 basalt 50 fossilization 50 striations 50 mussel shells 50 quartz crystals 50 magma chamber 50 icy crust 50 clam shells 50 moonlets 50 talus 50 greenish brown 50 tubules 50 manganese oxide 50 calcium carbonate 50 oxidization 49 threadlike 49 plankton blooms 49 microfossils 49 diatoms 49 ovoid 49 volcanic rock 49 isotopic composition 49 amphora 49 soft tissues 49 substratum 49 lavas 49 olivine 49 amphorae 49 apatite 49 carbonized 49 spalling 48 granuloma 48 mottled brown 48 glans 48 barnacle 48 tiny pores 48 whalebone 48 monazite 48 sediments 48 granulomas 48 colloid 48 abraded 48 globules 48 oxygen isotopes 48 sulphide minerals 48 mudstone 48 dentin 47 friable 47 fragments 47 silicon atoms 47 fibrous tissue 47 ship hull 47 marl 47 lava tubes 47 coarse sand 47 skull 47 nanoclusters 47 fatty tissue 47 carbonaceous 47 alternating layers 47 hydrothermal breccia 47 scanning electron microscopy 47 micelles 47 calcify 47 lakebed 47 silicates 47 diatom 47 chemically inert 47 sediment 47 microstructures 47 osmium 47 fossilized 47 hydrothermal activity 47 reddish 47 crystals 47 siliceous 47 outer crust 47 marine sediments 47 carnelian 47 obsidian 46 indentations 46 marine reptile