There is no section of our country that may not reward a diligent search for precious or useful minerals. The rocks, however, between the Alleghanies and the Atlantic and between the Rocky Mountains and the Pacific furnish the greater variety and abundance. Here are found the best ores. Gold and silver seem to abound more on the western than eastern sides of both mountain-chains. A trap-region, like the shore of Lake Superior and the Connecticut River Valley, is likely to be a good locality for copper and iron. The Mississippi Valley, or the region of Bituminous Coal, furnishes chiefly iron and lead; gold, silver and copper are seldom found. In general, where the layers of rock lie level and contain fossil shells, it is a locality good only for soft coal, (New York excepted), iron ore, gypsum and salt. The regions of granite, slate, limestone, marble, etc., offer the greatest inducement to search for useful minerals. CHAPTER II. DIRECTIONS FOR DETERMINING SPECIMENS BY THE KEY. HOW TO TEST MINERALS WITH THE SIMPLEST MEANS--PROSPECTING WITH A JACK-KNIFE AND COMMON SENSE--USE OF THE KEY--HOW TO TELL PYRITES FROM GOLD AND QUARTZ FROM DIAMOND--ALL THE USEFUL MINERALS GROUPED ACCORDING TO HARDNESS AND COLOR. First see whether it will scratch common window-glass. If it will make the least mark, it belongs to division A; if not, it is to be found in group B. Next notice whether the light will shine through it: if it does not pass through even the edges or a thin splinter, it is opaque; if any light is allowed to pass, it is translucent. With a knife see if it is harder or softer than pure white marble; then, noting its color, compare it with the descriptions of minerals referred to by the numbers. If it agree with none, it may be considered of no use in the arts. To make doubly sure, get the gravity as described on page 12. _Examples_: Suppose we have an unknown mineral in hand. We first try to scratch glass with it and find it impossible. It therefore belongs to section B. Next we find it is opaque and yellow, and evidently heavier and harder than marble. It must be one of two: 44 attracts the compass-needle, and this will not; it is consequently 26 or _Copper Pyrites_, if it agree with the description. If not, it is something of no great value.