![]() Obsidian, on the other hand, produces a fine and smooth edge that is highly sharp (many times sharper than a surgical steel scalpel). When a blade is made of surgical steel, due to the regularity of the microscopic structure of the material, the edge of the blade is always slightly rough no matter how sharp. Obsidian blades can be cut to a thickness of three nanometers (ten times thinner than common razor blades) with a very fine edge. While not approved by the FDA for use in human surgery, scalpel blades may be made from obsidian and have been used in experimental animal surgeries. More interestingly, obsidian is still used in surgical practices. Support stands for turntables have been made out of obsidian since the 1970s. Crystal balls made out of obsidian are popular in mystic settings. Obsidian is still used today in the making of decorative pieces such as jewelry and various carvings. Obsidian has also been used as a sort of back plating for pieces of opal jewelry, where a thin slab of obsidian is placed behind a piece of opal to add a dark background and provide better contrast for the rainbow hues of the opal. Beads can be made from obsidian, as well as earrings and brooches. Largely obsidian was used as a decorative ornament in various forms of jewelry. Obsidian has also been used to make carved masks or statues. In some cases, larger pieces of obsidian were polished as mirrors. Obsidian was not always used as a practical tool or weapon. ![]() Ancient Mesoamericans manufactured a type of sword called a macuahuitl which was made of wood and obsidian that could be used in slashing cuts to inflict wounds with the sharp and serrated edge. Knives and scrapers made of obsidian have also been found in archaeological sites. Obsidian has been used to make arrowheads and spearheads, as seen in the figure below. The conchoidal fracturing type of obsidian makes the rock an ideal material for weaponry and tools as flakes of obsidian can be chipped away leaving behind an incredibly sharp edge. This type of break occurs because obsidian is brittle, and an amorphous material that has no natural stress lines or planes of separation. This means that when the obsidian is struck and breaks, it does so with smooth, razor-sharp edges and curved surfaces. The fracture type of obsidian is conchoidal. Impurities can include iron oxide, magnetite nanoparticles, and minerals Primarily silica (silicon dioxide, SiO 2) What Are the Properties of Obsidian? Property Because obsidian is not the most stable rock as it can be worn down by natural elements, it is rare to find obsidian that is more than a few million years old. Obsidian can be found throughout the Americas, Australia, and Europe. Obsidian forms wherever there are volcanoes that emit lava that is rich in silica content, called felsic or rhyolitic lava. In order to form obsidian, the lava must cool quickly, without time to crystallize into a structured material, resulting in amorphous solid glass. Obsidian can also be formed when the lava flow meets water or solidifies in the air. These locations include the edge of a lava flow or a lava dome as viscous lava slowly pours out of the mouth of the volcano. Obsidian can be formed in several different locations around lava. When a volcano erupts and lava gushes forth to abruptly meet with a cooling element. When the mineral cristobalite is encased in the obsidian, it results in a rock with mottled white patches in the dark obsidian as seen above in the example of snowflake obsidian. Many variations of obsidian exist, and their appearance depends on the inclusion of impurities, such as iron which leads to dark brown or black obsidian. Obsidian is primarily made of silica, not unlike black tourmaline, but due to the fact that the obsidian forms quickly from the cooling lava, there is no time for a crystalline structure to form, resulting in the amorphous black glass called obsidian. An amorphous solid is not highly ordered in internal structure, unlike a crystal. This is because glass is amorphous, not crystalline in structure. A type of igneous rock, called extrusive igneous rock, obsidian is extruded from the Earth as lava which when rapidly cooled forms a natural glass.Īs a volcanic glass, obsidian is mineral-like, or mineraloid, but is not a true mineral. Obsidian, or lapis obsidianus, is essentially dark glass. ![]() Obsidian is an ancient rock that was discovered in Ethiopia by a Roman explorer named Obsidius. ![]() Obsidian is a natural glass formed by the meeting of lava from an erupting volcano with cold air or water, imbuing obsidian with all four elements: earth, fire, water, and air.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |