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  2. Obsidian - Wikipedia

    en.wikipedia.org/wiki/Obsidian

    Obsidian artifacts are common at Tell Brak, one of the earliest Mesopotamian urban centers, dating to the late fifth millennium BC. [44] Obsidian was valued in Stone Age cultures because, like flint, it could be fractured to produce sharp blades or arrowheads in a process called knapping.

  3. Obsidian use in Mesoamerica - Wikipedia

    en.wikipedia.org/wiki/Obsidian_use_in_Mesoamerica

    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.

  4. Opal - Wikipedia

    en.wikipedia.org/wiki/Opal

    Opals too thin to produce a "natural" opal may be combined with other materials to form "composite" gems. An opal doublet consists of a relatively thin layer of precious opal, backed by a layer of dark-colored material, most commonly ironstone, dark or black common opal (potch), onyx, or obsidian. The darker backing emphasizes the play of color ...

  5. Prismatic blade - Wikipedia

    en.wikipedia.org/wiki/Prismatic_blade

    The analysis of obsidian debitage can reveal whether or not prismatic blade production occurred at a site and, if it had, what stages of production the process included. In other words, the types of manufacturing waste present (e.g., rejuvenation flakes and/or blades, platform rejuvenation flakes, etc.) at a site can inform archaeologists about ...

  6. Shillourokambos - Wikipedia

    en.wikipedia.org/wiki/Shillourokambos

    Imported obsidian is rare, and sickles are made from single robust blades. The site is important because it attests to the presence of cattle in the aceramic Neolithic period. Cattle died out in the course of the 8th millennium and were not reintroduced until the ceramic Neolithic.

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  8. List of rock types - Wikipedia

    en.wikipedia.org/wiki/List_of_rock_types

    Quartzolite – Extremely rare igneous rock made mostly of quartz – An intrusive rock composed mostly of quartz; Rhyodacite – Volcanic rock rich in silica and low in alkali metal oxides – A felsic volcanic rock which is intermediate between a rhyolite and a dacite; Rhyolite – Igneous, volcanic rock, of felsic (silica-rich) composition

  9. List of blade materials - Wikipedia

    en.wikipedia.org/wiki/List_of_blade_materials

    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 ...