[Cannel Coal]
This is a compact variety of non-coking bituminous coal, with a dull luster and a conchoidal fracture. It contains the largest proportion of volatile hydrocarbon compounds of any variety of coal; so that when the supply of petroleum and natural gas gives out, this will be one of the important sources of obtaining substitutes. Cannel coals occur in Ohio, Indiana, and eastern Kentucky. This cannel coal owes its peculiar fatty nature to the material from which it is derived, it being supposed to have resulted from the accumulation of the spores of lycopod trees, and their conversion to jelly-like masses by bacteria in the fresh-water marshes of those ancient days.
[Anthracite]
hard coal
Anthracite coal is hard, black, has a luster, and breaks with a conchoidal fracture. It contains but a low percentage of volatile matter, and so burns with a short flame, and less smoke, than is the case with the other coals. It is always associated with folded rocks, and appears to have been formed as a result of the combined pressure and the higher temperatures, which accompanied mountain making. Still the temperature was not high enough to metamorphose the adjacent rocks. Most of our anthracite comes from northeastern Pennsylvania.
[Carbonite]
Carbonite is natural coke. It occurs in coal seams which have been cut by dikes or intrusions of igneous rocks, the coal having been thus coked by natural processes. It is not vesicular like artificial coke, for which reason it is not useful as a fuel. Some carbonite is found in the Cerillos coal field of New Mexico, in Colorado, and Virginia.
[Jet]
Jet is a dense variety of lignite, a fossil wood of black color, which takes a high polish and cuts easily into various ornamental shapes. It has been used for ornaments since early ancient times, beads of jet being found in the early bronze period in England, the supply probably coming from the Yorkshire coast, whence the principal supply comes even to the present day. In Switzerland and Belgium it was used still earlier, even as far back as the Palæolithic age. Jet seems then to have had a talismanic value, and to have been worn to protect the owner. About 700 A.D. crosses and rosaries began to be made of jet, the custom starting at Whitby Abbey, the material being obtained nearby, so that it came to be known as “Whitby jet,” and in the eighteenth century became very popular. In recent times it has been used mostly as jewelry suitable for mourning.
[Amber]
[Pl. 61]
Amber is a gum which oozed from coniferous trees and was petrified. It is associated with lignite beds of middle Tertiary age. It is usually pale-yellow in color, but at times has a reddish or brownish tinge, and is more or less transparent. It occurs in rounded irregular lumps, up to ten pounds in weight, though most pieces are smaller; and is mostly picked up along certain coasts where it is washed ashore by the waves. Since the earliest records amber has been cast up on the shores of the Baltic, and it was used by peoples as early as in the stone age for ornaments and amulets. It has been found among the remains of the cave dwellers of Switzerland, in Assyrian and Egyptian ruins of prehistoric age, and in Mycenæ in the prehistoric graves of the Greeks, the first recorded reference to it being in Homer, and the Greek name for amber being elektron from which our word electricity comes. All these finds were of Baltic amber which was doubtless gathered and traded by those early men. Even down to the present many men make their living, riding along the shore at low tide and hunting for the amber washed ashore by the waves. As early as 1860 the German geologists concluded that the source of the amber must be lignite beds outcropping beneath the sea level, and started mining for the amber with fair success, so that today two types of Baltic amber are distinguished, “sea stone” which is washed ashore, and “mine stone” taken from the mines. Beside the Baltic locality, it is found along the shores of the Adriatic, Sicily, France, China, and occasionally of North America.