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  2. Lithic analysis - Wikipedia

    en.wikipedia.org/wiki/Lithic_analysis

    In archaeology, lithic analysis is the analysis of stone tools and other chipped stone artifacts using basic scientific techniques. At its most basic level, lithic analyses involve an analysis of the artifact's morphology, the measurement of various physical attributes, and examining other visible features (such as noting the presence or absence of cortex, for example).

  3. Obsidian - Wikipedia

    en.wikipedia.org/wiki/Obsidian

    Iron and other transition elements may give the obsidian a dark brown to black color. Most black obsidians contain nanoinclusions of magnetite, an iron oxide. [25] Very few samples of obsidian are nearly colorless. In some stones, the inclusion of small, white, radially clustered crystals (spherulites) of the mineral cristobalite in the black ...

  4. Smoky quartz - Wikipedia

    en.wikipedia.org/wiki/Smoky_quartz

    Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals. [6] The color of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates color centers around aluminum impurities within the ...

  5. List of gemstones by species - Wikipedia

    en.wikipedia.org/wiki/List_of_gemstones_by_species

    Gemstones of the World revised 5th edition, 2013 by Walter Schumann ISBN 978-1454909538 Smithsonian Handbook: Gemstones by Cally Hall, 2nd ed. 2002 ISBN 978-0789489852 hide

  6. Color wheel - Wikipedia

    en.wikipedia.org/wiki/Color_wheel

    A color wheel or color circle [1] is an abstract illustrative organization of color hues around a circle, which shows the relationships between primary colors, secondary colors, tertiary colors etc. Some sources use the terms color wheel and color circle interchangeably; [ 2 ] [ 3 ] however, one term or the other may be more prevalent in ...

  7. Obsidian hydration dating - Wikipedia

    en.wikipedia.org/wiki/Obsidian_hydration_dating

    Obsidian hydration dating (OHD) is a geochemical method of determining age in either absolute or relative terms of an artifact made of obsidian.. Obsidian is a volcanic glass that was used by prehistoric people as a raw material in the manufacture of stone tools such as projectile points, knives, or other cutting tools through knapping, or breaking off pieces in a controlled manner, such as ...

  8. Porphyry (geology) - Wikipedia

    en.wikipedia.org/wiki/Porphyry_(geology)

    In its non-geologic, traditional use, the term porphyry usually refers to the purple-red form of this stone, valued for its appearance, but other colours of decorative porphyry are also used such as "green", "black" and "grey". [1] [2] The term porphyry is from the Ancient Greek πορφύρα (porphyra), meaning "purple".

  9. 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.