agate


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Related to agate: moss agate, black agate

agate

(ăg`ĭt), translucent, cryptocrystalline variety of quartzquartz,
one of the commonest of all rock-forming minerals and one of the most important constituents of the earth's crust. Chemically, it is silicon dioxide, SiO2.
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 and a subvariety of chalcedonychalcedony
[from Chalcedon], form of quartz the crystals of which are so minute that its crystalline structure cannot be seen except with the aid of a microscope. Chalcedony has a waxy luster and is translucent to transparent.
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. Agates are identical in chemical structure to jasper, flint, chert, petrified wood, and tiger's-eye, and are often found in association with opal. The colorful, banded rocks are used as a semiprecious gemstone and in the manufacture of grinding equipment. An agate's banding forms as silica from solution is slowly deposited into cavities and veins in older rock. The stones can be artificially stained to produce combinations of color more vivid than those found in the natural state. The cutting and staining of agates has long been centered at Idar-Oberstein, Germany. Important sources of agate are Brazil, Uruguay, and the United States (Oregon, Washington, and around Lake Superior). The moss agate or mocha stone contains visible impurities in the form of dendritic shapes that resemble moss. See onyxonyx
, variety of cryptocrystalline quartz, differing from agate only in that the bands of which it is composed are parallel and regular. Its appearance is most striking when the bands are of sharply contrasting colors; black and white specimens are often used for cameos.
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.

Agate

 

a mineral; a variety of chalcedony in the form of a dense, cryptocrystalline aggregate of fibrous or radial quartz formations (Si02)—so-called quartzite or α-tridymite. The mineral is characterized by multiple interstratification of thin (up to 10 microns), variously colored layers. The hardness of agate on the mineralogical scale is 6.0–6.5. The following varieties are recognized depending on the combination of colors in the layers—onyx (white and black layers), carnelian (red and white), sardonyx (reddish brown and white), and agates (bluish gray and white). Agate occurs in veins, in geodes, in amygdules among igneous rocks, and in the tuffs of the last. It is used as an industrial or semiprecious stone and in the manufacture of technical articles (bearing stones, prisms for scales, and so on). Agate is colored artificially to obtain bright, decorative forms.

G. P. BARSANOV

agate

[′ag·ət]
(graphic arts)
A type size in printing of about 5½ points, where 72 points equals 1 inch.
(mineralogy)
SiO2 A fine-grained, fibrous variety of chalcedony with color banding or irregular clouding.

agate

symbolizes health; supposed to relieve snake and scorpion bites. [Class. and Medieval Legend: Leach, 27]
See: Health

agate

confers this power. [Rom. Folklore: Brewer Dictionary,15]

agate

1. an impure microcrystalline form of quartz consisting of a variegated, usually banded chalcedony, used as a gemstone and in making pestles and mortars, burnishers, and polishers. Formula: SiO2
2. a playing marble of this quartz or resembling it
References in periodicals archive ?
At a time newspapers are seeking more and more ways to save money in printing -- and at a time when more and more consumers are buying computers for home use -- how long will it be before agate type is eliminated?
"Agates show us one way that nature makes repetitive patterns," Heaney says.
"Anyone in that Agate board room could have stood up and said, 'This seems like a little more money than we deserve.' As far as I know, nobody did," said a doctor and Agate shareholder who spoke to The Register-Guard on condition of anonymity.
The bizarre road rage incident came after black-haired Mrs Agate went to Sainsbury's in Purley Way, Croydon, Surrey, to collect last-minute items for a dinner party planned with her husband Alan, a businessman.
The troubled years leading up to Agate's sale and the big payouts to Agate shareholders have left critics of the sale bitter about how Trillium treated patients and worried about patients' future under Centene.
The $22 million apparently was paid to Agate's 218 shareholders in the same way the $109 million was paid.
The revenue growth, and Agate's track record of being able to pull increasing profits out of the money it was receiving from the government, burnished Agate's value.
Figures are based on individual shareholder information in Agate's official June 29, 2015, sales plan document, which was obtained by The Register-Guard.
It was publicly known that Centene bought Agate for $80 million to $130 million and that shareholders profited, but it wasn't known who got rich from the deal - or how rich.
On Saturday, expect closures and traffic changes in the University of Oregon neighborhood, including Agate Street to Fairmount Boulevard between 15th Avenue and 19th Avenue; 18th Avenue by the athletic fields; and Alder Street between 18th and 13th.
7, 2015): Several shareholders in Agate Resources Inc., the parent company of Trillium Community Health Plan, have sued the state and The Register-Guard to block release of records identifying Agate shareholders.