opal

o·pal

O0087300 (ō′pəl) n. 1. A mineral of hydrated silica. 2. A gemstone made of this mineral, noted for its rich iridescence.

[Early Modern English, from Middle French opale, from Latin opalus, alteration of Greek opallios, probably from Sanskrit upalaḥ, stone, precious stone (often in the sandhi form opalaḥ in the names of gems such as nīlopalaḥ, sapphire : nīla-, blue + upalaḥ), possibly variant of upara-, lower, from upa, towards, under, down; see upo in the Appendix of Indo-European roots.]

o′pal·ine′ (ō′pə-līn′, -lēn′) adj.

opal

(ˈəʊpəl) n (Minerals) an amorphous, usually iridescent, mineral that can be of almost any colour, found in igneous rocks and around hot springs. It is used as a gemstone. Composition: hydrated silica. Formula: SiO2.nH2O[C16: from Latin opalus, from Greek opallios, from Sanskrit upala precious stone] ˈopal-ˌlike adj

o•pal

(ˈoʊ pəl)

n. 1. a mineral, an amorphous form of silica, SiO₂, with some water of hydration, found in many varieties and colors, including milky white. 2. a gemstone made of this, esp. of an iridescent variety. [1350–1400; Middle English < Latin opalus < Greek opállios opal, gem]

o·pal

(ō′pəl) A usually transparent mineral consisting of hydrous silica. Opal can occur in almost any color, but it is often pinkish white with a milky or pearly appearance. It typically forms within cracks in igneous rocks, in limestones, and in mineral veins. It also occurs in the silica-rich shells of certain marine organisms.

Thesaurus

Noun

opal - a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstonesmineral - solid homogeneous inorganic substances occurring in nature having a definite chemical compositionblack opal - a dark colored opal with internal reflections of green or redfire opal, girasol - an opal with flaming orange and yellow and red colorsharlequin opal - a reddish opal with small patches of brilliant coloropaque gem - a gemstone that is opaque

Translations

乳色玻璃猫眼石蛋白石

opal

(ˈoupəl) noun a type of usually bluish-white or milky white precious stone, with slight traces or streaks of various other colours. There are three opals in her brooch; (also adjective) an opal necklace. 蛋白石，猫眼石，乳色玻璃

Opal

opal

(ō`pəl), a mineral consisting of poorly crystalline to amorphous silica, SiO₂·nH₂O; the water content is quite variable but usually ranges from 3% to 10%. Common opal is usually colorless or white, but it may be gray, brown, yellow, or red; the color is due to fine-grained impurities. Opal is formed at low temperatures from silica-bearing waters and can occur in fissures and cavities of any rock type. Precious, or gem, opal has a rich iridescence and remarkable play of changing colors, usually in red, green, and blue. This is the result of a specific internal structure consisting of regularly packed uniform spheres of amorphous silica a few tenths of a micron in diameter; sphere diameter and refractive index determine the range of colors displayed. The greater part of the world's supply of precious opal comes from the Coober Pedy and Andamooka fields in South Australia. The original source, known in Roman times, was in what is now E Slovakia. Precious opal has also been mined in Honduras, Mexico, and the Virgin Valley in Nevada. Fire opal is a bright red transparent or translucent opal that may or may not show a play of color.

Opal

a mineral; a compact natural hydrogel with composition SiO₂·nH₂ O. It occurs mainly as aggregates of extremely fine grains of low-temperature cristobalite. Most opal contains 2–14 percent H₂O; the usual admixtures include MgO, CaO, Al₂O₃, and Fe₂O₃.

Opal forms stalactitic, lamellar, or porous masses. Its hardness on Mohs’ scale is 5.0–6.5; its density is 1,800–2,250 kg/m³. The color varies, depending on the impurity content (white, yellow, brown); colorless varieties are also known. Translucent varieties are typically iridescent. The more common varieties include hyalite, which is colorless and clear; precious opal, with an attractive play of colors; and hydrophane, a porous semitranslucent opal. Certain rocks are composed entirely of opal—for example, geyserite, diatomite, and tripolite.

The formation of opal is associated with deposition of silica from hot volcanogenic waters or with decomposition of silica under the action of water and carbonic acid in the zone of weathering. The skeletons of diatoms and radiolarians form opal of biogenic origin. Colored iridescent opals are used as decorative stones; precious opal is a gemstone. Opal deposits in the USSR are found in the Ukraine and Kazakhstan, and abroad, in Hungary, Czechoslovakia, Mexico, and Australia. Among the opaline rocks, diatomites and tripolites have the greatest practical importance.

G. P. BARSANOV

opal

[′ō·pəl] (mineralogy) A natural hydrated form of silica; it is amorphous, usually occurs in botryoidal or stalactic masses, has a hardness of 5-6 on Mohs scale, and specific gravity is 1.9-2.2.

opal

A hydrous form of silica containing 2 to 10% combined water; reacts with cement alkalies and may be highly detrimental as an aggregate in concrete.

opal

October. [Am. Gem Symbolism: Kunz, 319–320]See: Birthstones

opal

unlucky stone; represents the Evil Eye. [Gem Symbolism: Kunz, 148, 320]See: Luck, Bad

opal

an amorphous, usually iridescent, mineral that can be of almost any colour, found in igneous rocks and around hot springs. It is used as a gemstone. Composition: hydrated silica. Formula: SiO₂.nH₂O

Opal

(1)A DSP language.

["OPAL: A High Level Language and Environment for DSP boardson PC", J.P. Schwartz et al, Proc ICASSP-89, 1989].

Opal

(2)The language of the object-oriented database GemStone.

["Making Smalltalk a Database System", G. Copeland et al, ProcSIGMOD'84, ACM 1984, pp.316- 325].

Opal

(3)A simulation language with provision for stochastic variables. An extension of Autostat.

["C-E-I-R OPAL", D. Pilling, Internal Report,C.E.I.R. Ltd. (1963)].

Opal

(4)A language for compiler testing said to be used internallyby DEC.

Opal

(5)A functional programming language designed at theTechnische Universitaet Berlin as a testbed for thedevelopment of functional programs. OPAL integratesconcepts from Algebraic Specification and FunctionalProgramming, which favour the (formal) development of (large)production-quality software written in a purely functionalstyle.

The core of OPAL is a strongly typed, higher-order,strict applicative language which belongs to the traditionof Hope and ML. The algebraic flavour of OPAL is visiblein the syntactical appearance and in the preference ofparameterisation to polymorphism.

OPAL supports: information hiding - each language unit isdivided into an interface (signature) and an implementationpart; selective import; parameterised modules; freeconstructor views on sorts, which allow pattern-basedfunction definitions despite quite different implementations;full overloading of names; puristic scheme language with nobuilt-in data types (except Booleans and denotations).

OPAL and its predecessor OPAL-0 have been used for some timeat the Technische Universitaet Berlin in CS courses and forresearch into optimising compilers for applicative languages.The OPAL compiler itself is writte entirely in OPAL.

An overview is given in "OPAL: Design And Implementation of anAlgebraic Programming Language".

http://cs.tu-berlin.de/~opal/.

ftp://ftp.cs.tu-berlin.de/pub/local/uebb/papers/DesignImplOpal.ps.gz.

Opal

The original name of software from CA Technologies that converts legacy output from mainframes and minicomputers into a graphical-based format. Now part of its Advantage Integration Server suite, the technology provides the development environment and supports 3270, 5250 and VT220 terminals and ODBC-compliant databases. Development can be done by drag and drop or by scripting in OpalScript or VBScript. A Telnet connection to the mainframe is provided and maintains a connection to the desktop allowing the Web browser or a Windows client with the software to have access to the newly formatted data. See green screen.

From Green Screen to the Web

Advantage Integration Server (formerly Opal) transforms legacy applications (top) into graphics-based documents (bottom) that can be accessed via a Web browser or Windows client software. (Screen examples courtesy of CA Technologies, Inc.)

From Green Screen to the Web

Advantage Integration Server (formerly Opal) transforms legacy applications (top) into graphics-based documents (bottom) that can be accessed via a Web browser or Windows client software. (Screen examples courtesy of CA Technologies, Inc.)

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Words related to opal

noun a translucent mineral consisting of hydrated silica of variable color

Related Words