Related by context. Frequent words. (Click for all words.) 62 tourmaline 60 feldspar 59 olivine 58 titanium oxide 56 iron oxides 55 silicate 55 nacre 55 malachite 54 iron oxide 54 quartz 54 garnets 53 molybdenite 53 silica 53 copper oxide 52 calcite 52 graphite 52 opal 51 jasper 51 chlorite 51 aluminum oxide 51 granites 51 quartz crystals 51 silicates 51 oxidised 50 basalt 50 chalcocite 50 amethyst 50 mudstone 49 pumice 49 limestones 49 cerium 49 hematite 49 topaz 49 metal oxides 49 limestone 49 pigments 49 oxidized 49 quartzite 49 metallic 49 crystals 48 pearlescent 48 gneiss 48 pigment 48 galena 48 alternating layers 48 iridium 48 schist 48 igneous 47 enamels 47 crystalline 47 travertine 47 alluvium 47 enamel 47 sulfides 47 silica sand 47 basalts 47 calcium carbonate 47 celadon 47 hydroxyapatite 47 carbonaceous 47 tungsten 47 bluish gray 47 opals 47 lacquer 47 oxides 47 gypsum 47 zirconia 47 mineral 47 cedar shingles 47 citrine 46 sintered 46 alloy 46 fluorite 46 ocher 46 matte 46 pyrite 46 Titanium dioxide 46 terracotta 46 ironstone 46 violet 46 glass beads 46 arsenopyrite 46 oxide 46 electrical conductivity 46 disseminated pyrite 46 electrolytic 46 sapphire 46 volcanic rock 46 Germanium 46 magnesium oxide 46 opalescent 46 resin 46 cobalt 46 semi precious stones 46 obsidian 45 titanium dioxide 45 Zirconium 45 varnish 45 indigo 45 sulphates 45 zinc oxide