174 



INDEX. 



Oxidizing agents, in 

 flame, 25 



pACOS ores, 77 



" Pan out " gold, to, 51 

 Parkes* process, 127 

 Pattinson's process, 127 

 Peridot, 97 

 Permian rocks, 17 

 Petroleum, 86 

 Pinching out of veins, 8 

 Pipeclay, 102 

 Pitchstone, 13, 100 

 Placer county, California, gold in, 



59 



Plasma, 97 

 Platinum, 74 



spongy, 74 



tests for, 29, 74, 108 



mechanical assay for, 74 

 Pleistocene rocks, 16 

 Pliocene rocks, 16 

 Plutonic rocks, 13 

 Porphyry, 13 



nature of, 99 

 Potash, colour of flame caused by, 



31 



as a reagent, 109 

 Potassium, cyanide of, 122, 129, 



130 



Potato-stone, 97 

 Precious stones, 89 



characteristics of, 95 

 Prism, 37 

 Prospecting for veins and deposits, 



shaft, 8 

 Psilomene, 70 

 Pumicestone, 13 

 Purple of Cassius in testing for 



gold, 108 

 Pyrargyrite, 77 

 Pyrites, arsenical, 63 



iron, 62 



magnetic, 62 



to distinguish from gold, 50 



iron, in auriferous quartz, 7 

 Pyrohisite, 69 



Pyromorphite, 68 

 Pyrope, 96 



QUARTZ, as a standard of hard 

 ** ness, 36 



characteristics of, 97 



matrix, 7, 104 



nature of, 104 



smoky, 97 



rose, 97 



weight of, Appendix 

 Quartz-porphyry, 13 

 Queensland, gold in, 57 

 Quicksilver, horn, 6 1 



REDUCING agents, HI 



" flame, 25 

 Rhyolite, 13, 6 1 

 Roasting, 123 

 Rock crystal, 97 



salt, hardness of, 36 

 Rocks, classification of, 13 



superposition of, 16, 17 

 Ruby, 89 



characteristics of the, 95 



copper, 47 



silver, 77 

 Russell's process, 128 



C ADDLE reefs, 57, 60 



Salt, common, 87 

 Saltpetre, 87 

 Sampling ore, ill 

 Sand, 14 

 Sandstone, 13, 101 



old red, 17 



flexible, 89 

 Sapphire, characteristics of, 95 



oriental, 95 



water, 96 

 Sard, 97 

 Sardonyx, 97 

 Schists, 13 



composition of, 99 



