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Wood Opal
Wood opal is a form of petrified wood which has developed an opalescent sheen or, more rarely, where the wood has been completely replaced by opal. Other names for this opalized sheen-like wood are opalized wood and opalized petrified wood. It is often used as a gemstone A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ....GEM HUNTER By George Frangoulis References Opals Gemstones {{Mineral-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petrified Wood
Petrified wood, also known as petrified tree (from Ancient Greek meaning 'rock' or 'stone'; literally 'wood turned into stone'), is the name given to a special type of ''fossilized wood'', the fossilized remains of terrestrial vegetation. ''Petrifaction'' is the result of a tree or tree-like plants having been replaced by stone via a mineralization process that often includes permineralization and replacement. The organic materials making up cell walls have been replicated with minerals (mostly silica in the form of opal, chalcedony, or quartz). In some instances, the original structure of the stem tissue may be partially retained. Unlike other plant fossils, which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes buried in water-saturated sediment or volcanic ash. The presence of water reduces the availability of oxygen which inhibits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opal
Opal is a hydrated amorphous form of silica (SiO2ยท''n''H2O); 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 in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. The name ''opal'' is believed to be derived from the Sanskrit word (), which means 'jewel', and later the Greek derivative (), which means 'to see a change in color'. There are two broad classes of opal: precious and common. Precious opal displays play-of-color ( iridescence); common opal does not. Play-of-color is defined as "a pseudo chromatic optical effect resulting in flashes of colored light from certain minerals, as they are turned in white light." The internal structure of precious opal causes it to di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gemstone
A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, and obsidian) and occasionally organic materials that are not minerals (such as amber, jet, and pearl) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones. Apart from jewelry, from earliest antiquity engraved gems and hardstone carvings, such as cups, were major luxury art forms. A gem expert is a gemologist, a gem maker is called a lapidarist or gemcutter; a diamond cutter is called a diamantaire. Characteristics and classification The traditional classification in the West, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opals
Optical Payload for Lasercomm Science (OPALS) is a spacecraft communication instrument developed at the Jet Propulsion Laboratory that was tested on the International Space Station (ISS) from 18 April 2014 to 17 July 2014 to demonstrate the technology for laser communications systems between spacecraft and ground stations. The purpose of OPALS is to do research into replacing traditional radio-frequency (RF) communications which are currently used on spacecraft. This will allow spacecraft to increase the rate at which data is downlinked by 10 to 100 times. It also will have less error than RF communication. It launched from Cape Canaveral to the ISS on 18 April 2014 on a Falcon 9 SpaceX CRS-3 Dragon capsule resupply. The experiment used commercial products rather than space qualified components. Science objectives The goal of the OPALS mission was to demonstrate a downlink of a short video from space using laser communication. In doing so, the following was studied: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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