Stone-Age is a term used to designate a stage of culture in man's development, not a chronological period in geological history. It refers to the period among any people when the use of metals is unknown or, if known at all, does not involve the knowledge of smelting. At such a time stone is largely used in making implements and tools, though other materials, as wood, bone and shell are also employed. The stone age is known to have existed in Europe many hundreds of years ago; in North America it continued among the Indians until the 18th century; in some other places it probably exists at the present time.

The great mass of evidence for the stone age has been gathered in western Europe, and that period has been subdivided into the paleolithic (old-stone) and neolithic (new-stone) eras. During the earlier time the implements were rudely chipped and left rough and irregular; in the later time they were often highly polished and finished with great care. Paleolithic man is thought to have existed in southern Europe while much of the continent was covered with ice. His presence there is known by the chipped flints found in place in beds of gravel and loess of France, which Prestwick and Lyell identify as drift-formations from the early ice invasion. Neolithic implements, specimens of which are much more numerous, have been collected in the oldest lake-dwellings of Switzerland and especially in Denmark. They are nowhere associated with river gravels, nor have paleolithic remains been found in Denmark. In that country the polished stone-implements and bits of pottery found in the shell-heaps of kjökken-mödding (kitchen-middens) indicate that man had reached a higher stage of culture by the time he had reached that region in his northward migration after the retreating ice-sheet. In America the same subdivision of periods has been attempted, but thus far the evidence seems to show the presence of neolithic man only. The specimens brought forward to prove the presence of paleolithic man seem to be rude “rejects” thrown aside before completion.

Stone-Circles or Standing-Stones are groups of stones, sometimes two or three standing alone and sometimes arranged in circles, found in Britain, Scandinavia, France and elsewhere. They were called druidical circles in Britain, cromlechs in France and dom-rings in Scandinavia. Sometimes they are bowlders rolled into place, and sometimes pillar-stones, fastened in position by smaller ones at the base. Sometimes there is a single circle, and again there will be one or two smaller circles within. Examination of these circles in Scotland proves that they were cemeteries of the bronze age. The largest stone-circle in Scotland is that of Stennis, Orkney. It is surrounded by a trench 30 feet wide and six feet deep, inclosing two and a half acres. There are 13 stones still standing, the highest being 14 feet.

Stone'henge is a circle of stones on Salisbury Plain, England, and was classed as one of the four wonders of England. It is a set of circles and oval figures. The first circle has pillars of stone about 13 feet high and four feet apart, and stones placed across on top. There are about 140 stones of the different circles, some being 23 feet high. It is also found to be a burial-place. The stone circles of Norway and Sweden seem to be burial-places of the iron age. The circles are rare south of the Baltic, there being only a few in France and Algeria. Consult Fergusson's Rude Stone Monuments.

Stone, Lucy (Blackwell), American reformer and advocate of woman's rights, was born at West Brookfield, Mass., Aug. 13, 1818, and died at Dorchester, Mass., Oct. 18, 1893. Graduating at Oberlin College in 1847, she devoted herself to advocacy of woman-suffrage and to antislavery, for which she became a zealous worker. She lectured widely in favor of woman-suffrage, organizing wherever she went local societies of the Woman's Suffrage Association, of which she was one of the founders as well as editor of the (Boston) Woman's Journal, its mouthpiece. She aided in organizing, in 1850, the first national woman's rights convention at Worcester, Mass., and was always zealous in the cause she held dear to her heart. In 1855 she married Henry B. Blackwell, though stipulating to bear her maiden name.

Stones, Precious, are mineral substances used in jewelry and for other ornamental purposes. They are called precious because of their rarity and expensiveness. The diamond, ruby, sapphire, oriental amethyst and emerald stand first in the list of precious stones, because of their brilliant color, luster, hardness, durability and rarity. The topaz, garnet, turquoise, tourmaline, opal, agate, jasper and onyx are of the second class, while there is still a large class of stones used for ornaments, as lapis-lazuli, malachite and the moonstone, which are not called precious stones. There also are two substances, derived from animals, used in jewelry: pearls and corals; and also amber, which is a fossil resin. The cutting and polishing of precious stones are necessary to bring out the sparkle and luster so highly valued. When the sparkle is desired, the stone is cut with many faces or facets, as in the diamond, but when the color is important, it is cut with a smooth and usually rounded surface. The hardness of the stone adds to its value, as it admits of a higher polish, retains it longer and wears better. The diamond is the hardest of the precious stones. The great value of these stones has led to many efforts to produce artificial imitations but without success. The usual imitations are made of a soft flint-glass, called stress or paste, which is colored and sometimes has thin plates of the real stone over of under it. See Diamond, Pearl and Sapphire.

Stoneworts (wûrtz), the common name of species of Characeæ (q. v.)

Stony Point, a rocky point on Hudson River, 42 miles north of New York. There was a fort here, and one on the point opposite, during the Revolutionary War, which were captured by the British, but the Stony Point fort was retaken by Anthony Wayne in a bold night attack, July 16, 1779.