P Pacific 33, 41 Paint ore 58 Paleontology 71 Paris 33 Petrified wood 35, 43, 69 Petroleum 71 Phelps County 26, 27 Phenocrysts 46 Pilot Knob 56 Plagioclase feldspar 44, 49, 74 Plaster of paris 63 Plastic fire clay 26 Polish on marble and granite 16 Pop-corn flint fire clay 26 Porphyry 31, 40, 44, 45, 53, 73 Porphyry, chemical composition 40 Potosi 37 Pyrite 14, 49, 51, 52, 53, 57, 58, 63, 66, 74 Pyroxene 49, 74 Q Quarry 14 Quartz 30, 38, 39, 40, 41, 45, 49, 54, 65, 68, 74 Quartzite 32, 55, 73 R Radioactivity 66 Reynolds County 58 Rhyolite, rhyolite porphyry 45, 71, 73 Ripple marks 33 Rock crystal 42 Rock, definition 5, 73 Rock wool 13 Rose quartz 42 Rosin jack zinc ore 60 Rosin spar zinc ore 60 Ruby jack zinc ore 60