Obsidian and rock crystal were also used for knife making.
It is probable that the acropolis of Carales was occupied even in prehistoric times; but more abundant traces of prehistoric settlements (pottery and fragments of obsidian, also kitchen middens, containing bones of animals and shells of molluscs used for human food) have been found on the Capo S.
Numerous fragments of obsidian arrow-heads and chips are also found in and near them all over the island.
Like the rest of the cluster, the island is of volcanic origin, with tuff, trachyte and obsidian among its ordinary rocks.
Another type of incipient crystallization which is excessively common in obsidian is spherulites, or small rounded bodies which have a radiating fibrous structure.
The polished battle-axe was more used in Grand Canary, while stone and obsidian, roughly cut, were commoner in Teneriffe.
South-east of the harbour, a neolithic village was situated, with a rampart of small blocks of obsidian, about 25 ft.
Wide at the base, and 16 at the top, upon the undefended eastern side: within it remains of huts were found, with pottery, tools of obsidian, &c. The objects discovered are in the museum at Syracuse.
The Nahuatl lapidaries had at hand many varieties of workable and beautiful stone - onyx, marble, limestone, quartz and quartz crystal, granite, syenite, basalt, trachyte, rhyolite, diorite and obsidian, the best of material prepared for them by nature; while the Mayas had only limestone, and hard, tenacious rock with which to work it, and timber for burning lime.
The archers shot well and with strong bows, though their arrows were generally tipped only with stone or bone; their shields or targets, mostly round, were of ordinary barbaric forms; the spears or javelins had heads of obsidian or bronze, and were sometimes hurled with a spear-thrower or atlatl, of which pictures and specimens still exist, showing it to be similar in principle to those used by the Australians and Eskimo.
The most characteristic weapon of the Mexicans was the maquahuitl or " handwood," a club set with two rows of large sharp obsidian flakes, a well-directed blow with which would cut down man or horse.
On the paved platform were three-storey tower temples in whose ground-floor stood the stone images and altars, and before that of the war-god the green stone of sacrifice, humped so as to bend upward the body of the victim that the priest might more easily slash open the breast with his obsidian knife, tear out the heart and hold it up before the god, while the captor and his friends were waiting below for the carcase to be tumbled down the steps for them to carry home to be cooked for the feast of victory.
Iron was not known, but copper and tin ores were mined, and the metals combined into bronze of much the same alloy as in the Old World, of which hatchet blades and other instruments were made, though their use had not superseded that of obsidian and other sharp stone flakes for cutting, shaving, &c. Metals had passed into a currency for trading purposes, especially quills of gold-dust and T-shaped pieces of copper, while coco-beans furnished small change.
They perform complicated surgical operations with an obsidian knife or a shark's tooth.
Breakfast was on the magic obsidian tray next to the bed.
It was sensual, dark and cool: black walls and obsidian wood flooring covered by jewel-toned rugs, mahogany California King bed with the finest maroon silk sheets and a dark gray comforter so soft, it was like sleeping in a cloud.
The only place where obsidian is known to be found in Sardinia in a natural state is the Punta Trebina, a mountain south-east of Oristano.
(4) Commerce was practised to some extent in very early times, as is proved by the distribution of Melian obsidian over all the Aegean area and by the Nilotic influence on early Minoan art.
To Melos in the earlier Second City Period of Phylakope) and to Cyprus, receiving in return such commodities as Melian obsidian knives.
Celts, of the usual late neolithic type, were generally of green jasper; hoe-blades (looking almost exactly like palaeolithic haches a main) of chert or coarse limestone; hammers of granite; mace-heads, of identical type with the early Egyptian, of diorite and limestone; nails of obsidian or smoky quartz, often beautifully made.
The position of Melos, between Greece and Crete, and its possession of obsidian, made it an important centre of early Aegean civilization.
OBSIDIAN, a glassy volcanic rock of acid composition.
Rhyolitic lavas frequently are more or less vitreous, and when the glassy matter greatly predominates and the; crystals are few and inconspicuous the rock becomes an obsidian; the chemical composition is essentially the same as that of granite; the difference in the physical condition of the two rocks is due to the fact that one consolidated at the surface, rapidly and under low pressures, while the other cooled slowly at great depths and under such pressures that the escape of the steam and other gases it contained was greatly impeded.
Few obsidians are entirely vitreous; usually they have small crystals of felspar, quartz, biotite or iron oxides, and when these are numerous the rock is called a porphyritic obsidian (or hyalo-liparite).
The chemical composition of typical obsidians is shown by the following analyses Obsidian, when broken, shows a conchoidal fracture, like that of glass, and yields sharp-edged fragments, which have been used in many localities as arrow-points, spear-heads, knives and razors.