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Obsidian (/ ə b ˈ s ɪ d i. ən, ɒ b-/ əb-SID-ee-ən ob-) [5] is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. [6] Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.
Obsidian is a naturally formed volcanic glass that was an important part of the material culture of Pre-Columbian Mesoamerica. Obsidian was a highly integrated part of daily and ritual life, and its widespread and varied use may be a significant contributor to Mesoamerica's lack of metallurgy.
The most common blade materials are carbon steel, stainless steel, tool steel, and alloy steel. Less common materials in blades include cobalt and titanium alloys, ceramic, obsidian, and plastic. The hardness of steel is usually stated as a number on the Rockwell C scale (HRC). The Rockwell scale is a hardness scale based on the resistance to ...
Website. obsidian.md. Obsidian is a personal knowledge base and note-taking software application that operates on Markdown files. [3][4][5] It allows users to make internal links for notes and then to visualize the connections as a graph. [6][7] It is designed to help users organize and structure their thoughts and knowledge in a flexible, non ...
Spear-armed hoplite from Greco-Persian Wars. A spear is a polearm consisting of a shaft, usually of wood, with a pointed head.The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fastened to the shaft, such as bone, flint, obsidian, copper, bronze, iron, or steel.
Prismatic blade. In archaeology, a prismatic blade is a long, narrow, specialized stone flake tool with a sharp edge, like a small razor blade. [1] Prismatic blades are flaked from stone cores through pressure flaking or direct percussion. [2] This process results in a very standardized finished tool and waste assemblage.
Mirrors in pre-Columbian Mesoamerica were fashioned from stone and served a number of uses, from the decorative to the divinatory. [3] An ancient tradition among many Mesoamerican cultures was the practice of divination using the surface of a bowl of water as a mirror. At the time of the Spanish conquest this form of divination was still ...
Mohs scale. The Mohs scale (/ moʊz / MOHZ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by the German geologist and mineralogist Friedrich Mohs, in his book Versuch einer ...