obsidian (ŏbsĭd`ēən), a volcanic glass glass, hard substance, usually brittle and transparent, composed chiefly of silicates and an alkali fused at high temperature. Composition and Properties of Glass

..... Click the link for more information. , homogeneous in texture and having a low water content, with a vitreous luster and a conchoidal fracture. The color is commonly black, but may be some shade of red or brown, and cut sections sometimes appear to be green. Like other volcanic glasses, obsidian is a lava lava , molten rock that erupts on the earth's surface, either on land or under the ocean, by a volcano or through a fissure. It solidifies into igneous rock that is also called lava.
..... Click the link for more information. that has cooled too quickly for the contained minerals to crystallize. In chemical composition it is rich in silica and similar to granite. It is favored by primitive peoples for knives, arrowheads, spearheads, and other weapons and tools.

obsidian

Natural glass of volcanic origin that is formed by the rapid cooling of viscous lava. It has a glassy lustre and is slightly harder than window glass. It is typically jet black, but the presence of hematite (iron oxide) produces red and brown varieties, and tiny gas bubbles may create a golden sheen. It is sometimes used as a semiprecious stone. Obsidian was used by American Indians and others for weapons, implements, tools, and ornaments, and by the ancient Aztecs and Greeks for mirrors.

obsidian

a dark volcanic glass formed by very rapid solidification of lava

obsidian [äb′sid·ē·ən]

(geology)

A jet-black volcanic glass, usually of rhyolitic composition, formed by rapid cooling of viscous lava; generally forms the upper parts of lava flows. Also known as hyalopsite; Iceland agate; mountain mahogany.

obsidian

A natural volcanic glass, usually black, with a bright luster; has relatively low water content.

Obsidian

(Latin Obsidianus lapis, “Obsidius’ stone”; according to Pliny the Elder, the rock was discovered in Ethiopia by a certain Obsidius, or more accurately, Obsius), a homogeneous vitreous volcanic rock, usually dark-colored (black, reddish black), with a marked conchoidal fracture. The hardness on Mohs’ scale is 5, and the density, is 2,500–2,600 kg/m³. The rock contains about 0.5 percent water.

Obsidian polishes well. It is formed upon hardening of the viscous varieties of rhyolite lava or rhyodacite lava. Certain varieties of obsidian are used as decorative stones. In the Stone Age and Bronze Age, obsidian was used to make arrowheads, spearheads, knives, and scrapers. At present it is used mainly as an expanding filler for lightweight concretes. Obsidian is found in areas of volcanic activity—for example, in Transcaucasia and on Kamchatka in the USSR, and also in Italy and Mexico.

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No references found	The late Don Crabtree, who, although unschooled, singlehandedly put the academic study of knapping on a practical footing, had long advocated the benefits of using obsidian scalpel blades in surgery, this observed from his own quickly healed wounds whenever he accidently cut himself with a flake. Flintknapping comes of age; anthropologists and hobbyists alike have ... by Werner, Louis / Americas (English Edition)	Observatory observatory, orbiting observed fire observed latitude observed longitude observed position observer Observer Status Observer, The observing angle obsession Obsessions obsessive-compulsive disorder obsessive-compulsive neurosis obsessive-compulsive personality Obsessiveness Obsha Obshchedeltsy Obshchee Delo Obshchee Veche Obshchestvennoe Pitanie Obshchii Syrt Obshchina Obsidian obsidian hydration method Obsidian scalpel obsidianite obsolescence Obsolescence of Fixed Capital obsolete obstacle obstacle clearance obstacle clearance box obstetric Obstetric Care obstetric forceps obstetrical analgesia obstetrician Obstetrics obstetrics and gynecology Obstinacy obstipation obstructed stream obstruction obstruction beacon obstruction buoy obstruction light obstruction marker obstruction moraine obstruction to vision obstructionist	obsessively obsessively obsessiveness obsessiveness obsessiveness obsessives obsessives obsessivity obsessor obsessor Obsevatory Magnetometer Interface System OBSF OBSF OBSG OBSGEN OBSH Obsha Obshchedeltsy Obshchee Delo Obshchee Veche Obshchestvennoe Pitanie Obshchestvennoe Rossiiskoe Televidenie Obshchii Syrt Obshchina OBSI obsidian obsidian Obsidian Hydration Analysis Service obsidian hydration method Obsidian Sanctum Obsidian scalpel obsidianite obsidio Obsidional Obsidional crown Obsigillation Obsign Obsignate Obsignation Obsignatory OBSINTEL OBSIP obsistere OBSK OBSL OBSM OBSN OBSO OBSOC obsolesce obsolesce obsolesced obsolesced obsolescence obsolescence obsolescence obsolescence obsolescence Obsolescence Management Obsolescence Management Obsolescence Management

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The late Don Crabtree, who, although unschooled, singlehandedly put the academic study of knapping on a practical footing, had long advocated the benefits of using obsidian scalpel blades in surgery, this observed from his own quickly healed wounds whenever he accidently cut himself with a flake.

Flintknapping comes of age; anthropologists and hobbyists alike have ... by Werner, Louis / Americas (English Edition)

Obsidian (redirected from Obsidian scalpel)

obsidian

Obsidian
(redirected from Obsidian scalpel)