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Decoupage or découpage ( / ˌdeɪkuːˈpɑːʒ /; [ 1] French: [dekupaʒ]) is the art of decorating an object by gluing colored paper cutouts onto it in combination with special paint effects, gold leaf, and other decorative elements. Commonly, an object like a small box or an item of furniture is covered by cutouts from magazines or from ...
Triboluminescence of nicotine L -salicylate. Triboluminescence is a phenomenon in which light is generated when a material is mechanically pulled apart, ripped, scratched, crushed, or rubbed (see tribology ). The phenomenon is not fully understood but appears in most cases to be caused by the separation and reunification of static electric ...
Geode. A geode ( / ˈdʒiː.oʊd /; from Ancient Greek γεώδης (geṓdēs) 'earthlike') is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded. The crystals are formed by the filling of vesicles in ...
Opal is a hydrated amorphous form of silica (SiO 2 · n H 2 O); its water content may range from 3% to 21% by weight, but is usually between 6% and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals. It is deposited at a relatively low temperature and may occur ...
Pumice is widely used to make lightweight concrete and insulative low-density cinder blocks. The air-filled vesicles in this porous rock serve as a good insulator. [18] A fine-grained version of pumice called pozzolan is used as an additive in cement and is mixed with lime to form a light-weight, smooth, plaster-like concrete.
The skin and bones of the gods were believed to be made of gold. The Egyptians used yellow ochre extensively in tomb painting, though occasionally they used orpiment, which made a brilliant colour, but was highly toxic, since it was made with arsenic. In tomb paintings, men were always shown with brown faces, women with yellow ochre or gold faces.
Hardstone carving, in art history and archaeology, is the artistic carving of semi-precious stones (and sometimes gemstones ), such as jade, rock crystal (clear quartz ), agate, onyx, jasper, serpentinite, or carnelian, and for objects made in this way. [1] [2] Normally the objects are small, and the category overlaps with both jewellery and ...
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of ...