![]() ↑ Obsidian was also used on Rapa Nui ( Easter island) for edged tools such as Mataia and the pupils of the eyes of their Moai (statues).↑ "Perlite - Mineral Deposit Profiles, B.C.Primitive technology: a book of Earth skills. ↑ Obsidian is found in rhyolitic lava flows known as obsidian flows.When cut in one direction it is a beautiful jet black when cut across another direction it is glistening gray. It possesses the property of presenting a different appearance according to the manner in which it is cut. Obsidian is also used for ornamental purposes and as a gemstone. ![]() One study found that obsidian produced narrower scars, fewer inflammatory cells, and less granulation tissue in a group of rats. When examined under an electron microscope an obsidian blade is still smooth and even. Even the sharpest metal knife has a jagged, irregular blade when viewed under a strong enough microscope. Obsidian is used in heart surgery, as well-crafted obsidian blades have a cutting edge many times sharper than high-quality steel surgical scalpels, with the edge of the blade being only about 3 nm wide. Obsidian can also be found in Armenia, Turkey, Italy, Mexico, Iceland, Greece and Scotland.Ĭurrent use Pig carved in snowflake obsidian, 10 centimeters (4 in) long. Deposits can be found in many other western US states including Arizona, Colorado, Texas, Utah, Oregon and Idaho. Yellowstone National Park has a mountainside containing obsidian between Mammoth Hot Springs and the Norris Geyser Basin. There are solid obsidian flows in the calderas of Newberry Volcano and Medicine Lake Volcano in the Cascade Range of western North America, and at Inyo Craters east of the Sierra Nevada, California. ![]() Obsidian can be found where high silicate eruptions have happened. Modern archaeologists have developed a dating system to calculate the age of obsidian artifacts depending from the content of water in the object. Obsidian cores (unworked lumps) and blades were traded great distances inland from the coast. Obsidian can be identified in Greece as coming from different islands in the Aegean Sea. So archaeologists can trace the origins of a particular artifact. Each volcano and in some cases each volcanic eruption produces a distinguishable type of obsidian. Native American people traded obsidian throughout North America. Called a macuahuitl, the weapon could cause terrible injuries, because it combined the sharp cutting edge of an obsidian blade with the ragged cut of a serrated edge. Mesoamericans also made a type of sword with obsidian blades mounted in a wooden body. It was also polished to create early mirrors. It was worked for tools and decorative objects. Pre-Columbian Mesoamericans used obsidian often. Obsidian was valued in Stone Age cultures because, like flint, it could be chipped to produce hand axes, sharp blades or arrowheads. It may contain patterns of gas which produce effects such as a golden sheen ( sheen obsidian) or a rainbow sheen ( rainbow obsidian). In some stones, small crystals produce a snowflake pattern ( snowflake obsidian). Iron and magnesium typically give the obsidian a dark green to brown to black color. Usually dark, the color varies on the presence of different materials. Obsidian has little water, but takes it in if it sits in groundwater. It breaks down faster when water is present. So, no unaltered obsidian is older than Cretaceous age. Over time, the glass becomes fine-grained crystals. It is metastable: it changes very slowly. It consists mainly of SiO 2 ( silicon dioxide), usually 70% or more. Obsidian is mineral-like, but not crystalline. They were used as arrowheads, and today they may be used as surgical scalpel blades. Because there is no crystal structure, obsidian blade edges can reach almost molecular thinness. It is produced when lava high in silica (SiO 2) cools rapidly, and solidifies quickly. Obsidian is a natural volcanic glass: it is a kind of igneous rock. Counterclockwise from top: obsidian, pumice and rhyolite (light color) ![]() Glass Mountain, a large obsidian flow at Medicine Lake Volcano. For other uses, see Obsidian (disambiguation).
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