Silver, 70, 71 and gold, consumption in the arts in the United States, 137, 138 and gold, production of the United States, 137, 138 glance, 71 localities, 71 reducing, 100 value, 71 horn, 53 in copper ores, 101 in lead and copper ores, 99 in lead ore, to detect, 99 to estimate the proportion of, 99, 100 in Nevada, 134-137 localities, 70 native gold in, 97 ore, assay of, 99, 100 brittle, 30 red, 66 ores, rich reduction of, 100 pure easily recognized, 99 searching for, 80, 90 to test a globule of for gold, 97 to test copper ores for, 99 where found, 89 Slate regions, 14 Smaltine, 72 localities, 72 value, 72 Smithsonite, 72 localities, 72 value, 72 Spar manganese, 60 Spathic iron, 73 localities, 73 value, 73 Specific gravity, mode of determination of, 12, 13 Specular iron ore, 73, 74 localities, 74 value, 74 Spinel ruby, 74 localities, 74 value, 74 Steatite, 75 localities, 75 value, 75 Stones, precious, color and order of hardness, 126 Strass for making false jewels, 115 Strontianite, 75, 76 localities, 76 value, 76 Sulphur, 76 localities, 76 springs, 108, 109 Testing minerals, 15-19 Thermal springs, 110, 111 Tin ore, 76, 77 assay of, 102, 103 localities, 77 value, 76 presence of, testing for, 103 Topaz, 77 characteristics of, 85 false, how made, 116 localities, 77 to test, 118, 120, 123 value, 77 Tourmaline, 77 localities, 77 to test, 123 value, 77 Translucent minerals, 12 Trap regions, 14 True and false gems, how to distinguish, 117-124 United States, consumption of gold and silver in the arts, 137, 138 gold and silver statistics of, 137, 138 Useful minerals, descriptive list of, 20-80 in the United States 11 Valuable minerals disguised, 10 Variegated copper ore, 78 localities, 78 value, 78 Veins, lodes and beds most valuable, 82 Virginia group, silver mines, 136 Wad, 78, 79 localities, 79 value, 78 Warm springs, 110, 111 Washing for gold and platinum, 94, 95 Washoe lake, silver mines near, 134 Wells, artesian, 111, 112 Willemite, 79 localities, 79 value, 79 Zincite, 79, 80 localities, 80 value, 79 Zinc ore, assay of, 102 FOOTNOTES: [1] The useful rocks, as granite, slate, sandstone, water-lime, etc., are not included. By “granite region” is meant one having rocks like New England, and therefore unlike Western New York or Illinois. [2] That is, they are not so easily cut with a knife; they do not necessarily scratch marble. [3] Only the best known localities in the United States are given. For these we are indebted mainly to Professor Dana’s great work on Mineralogy. [4] From Simonin’s “_Underground Life_,” page 346. [5] Church. The Comstock Lode, its Formation and History, N. Y., 1879, pp. 1-5. End of the Project Gutenberg EBook of Underground Treasures: How and where to find them, by James Orton