Asphalt
or ASPHALTUM, the most common variety of bitumen; also called mineral pitch. Asphalt is a compact, glossy, brittle, black or brown mineral, which breaks with a polished fracture, ASPHODEL melts easily with a strong pitchy odor when heated, and when pure burns without leaving any ashes. It is found in the earth in many parts of Asia, Europe, and the United States, and in a soft or liquid state on the surface of the Dead Sea, which, from its circumference, was called Asphaltites. It is of organic origin, the asphalt of the great Pitch Lake of Trinidad being derived from bituminous shales, containing vegetable remains in the process of transformation. Asphalt is produced artificially in making coal gas.
What is known of asphalt rock is a limestone impregnated with bitumen, found in large quantities in Switzerland, France, Hanover, Holstein, Sicily, and other parts of Europe, and in the United States, the purest forms taking the names of elaterite, gilsonite, albertite, maltha, brea, etc. In the trade there is wide distinction between these and the sandstones, and limestones impregnated with bitumen, which are known as bituminous or asphaltic limestone, sandstone, etc. The latter are usually shipped without being previously treated or refined, and are used principally in street paving.
The production of asphalt in the United States, produced from domestic petroleum, was in 1918, 527,575 tons, valued at $7,435,204. There were produced from Mexican petroleum in the same year 650,244 tons, valued at $10,- 324,200. The production of bitumines and allied substances in 1918 amounted to 60,034 tons, valued at $780,808. The crude asphalt imported into the United States in 1918 amounted to 114,686 short tons, valued at $624,967. There were exported in the same year 22,108 tons, valued at $577,654.