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Obsidian projectile point.. 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 source of obsidian for cultures inhabiting the territory of and around Greece was the island of Milos; the Starčevo–Körös–Criș culture obtained obsidian from sources in Hungary and Slovakia, while the Cardium-Impresso cultural complex acquired obsidian from the island outcrops of the central Mediterranean.
The natural volcanic glass obsidian can achieve a nearly molecular edge (high achievable sharpness) and only requires Stone Age technology to work, [2] but is so brittle that it cannot maintain that sharpness for very long. Additionally, The entire blade is highly susceptible to being accidentally broken.
Ingot molds are tapered to prevent the formation of cracks due to uneven cooling. A crack or void formation occurs as the liquid to solid transition has an associated volume change for a constant mass of material. The formation of these ingot defects may render the cast ingot useless and may need to be re-melted, recycled, or discarded.
It is uncertain whether the oxhide ingots served as a form of currency. Ingots found in excavations at Mycenae are now part of the exhibits of the Numismatic Museum of Athens. Cemal Pulak argues that the weights of the Uluburun ingots are similar enough to have allowed "a rough but quick reckoning of a given quantity of raw metal prior to ...
The "black" in "blacksmith" refers to the black firescale [citation needed], a layer of oxides that forms on the surface of the metal during heating.The origin of smith is the Old English word smið meaning "blacksmith", originating from the Proto-Germanic *smiþaz meaning "skilled worker".
Gases and liquids can also be refined by extraction with a selective solvent that dissolves away either the substance of interest, or the unwanted impurities. Many solids can be refined by growing crystals in a solution of the impure material; the regular structure of the crystal tends to favor the desired material and exclude other kinds of ...
In the Americas, pre-Inca civilizations of the central Andes in Peru had mastered the smelting of copper and silver at least six centuries before the first Europeans arrived in the 16th century, while never mastering the smelting of metals such as iron for use with weapon craft. [9]