Mineralogy
the study of minerals. It discusses crystals and the laws of their formation. The physical properties of minerals are investigated with reference to light, heat, and electricity. Hardness, tenacity, elasticity, cleavage, and fracture are discussed, as well as taste, odor, and touch. Alum, for instance, has an astringent taste; saltpeter, a cooling taste; sulphuric acid is sour; zinc sulphate, metallic in taste. Arsenical iron has the odor of garlic; roasted selenium smells like horseradish. Certain varieties of limestone give off the odor of rotten eggs when rubbed, etc. Talc feels greasy; genuine gems feel cold; glass feels warm. The mineralogist classifies rocks also with reference to their original structure, composition, crystalline character, etc. Over a thousand minerals have received names. See Granite; Marble; Diamond; Hardness, etc.
Mineral Products of the United States. In 1909 the Conservation Commission made a report on the mineral products and resources of the country, embodying valuable statistics. According to this report, the total output for 1907 exceeded $2,000,000,000. The chief mineral products were:
Hard coal, tons ..... 85,000,000
Petroleum, barrels ..... 166,000,000
Iron ore, high grade, tons ..... 45,000,000
Iron ore, low grade, tons ..... 45,000,000
Phosphate rock, tons ..... 2,500,000
Copper, pounds ..... 896,000,000
Clay products, value ..... $162,000,000
Stone ..... $71,000,000
Cement ..... $56,000,000
Natural gas ..... $50,000,000
Gold ..... $90,000,000
Silver ..... $37,000,000
Lead ..... $39,000,000
Zinc ..... $26,000,000
In the same report the committee estimated the known supply of American coal at 1,400,000,000,000 tons, enough to last 150 years at present rate of consumption; high grade iron ore, 3,840,000,000 tons, enough for 50 years; petroleum, 20,000,000,000 barrels, sufficient for 50 years.
Many are becoming alarmed lest our supply of useful minerals be exhausted. From a chemical point of view, it is true that not an atom of any mineral can be annihilated or destroyed, but it is none the less probable that once the mineral atoms that have accumulated in the earth during geologic ages have been scattered, not all the ingenuity of man can gather them together again. It is quite possible that aluminum, as plentiful as clay, and sunshine, the gift of the sun, may take the place of iron and coal; but none the less it behooves a thoughtful people to be frugal in the use of nature's bounties.
See Coal; Iron; Gas; Copper; Gold