Tarnish


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tarnish

[′tär·nish]
(metallurgy)
Discoloration of a metal surface due to the formation of a thin film of oxide, sulfide, or some other corrosion product.
(mineralogy)
The altered color and luster of a mineral surface; characteristic of copper-bearing minerals.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Tarnish

 

the variegated, often iridescent, coloring of a thin surface layer of a mineral, differing sharply from the color of the rest of the mineral. Tarnish is caused by the presence, on the surface of the mineral grains, of a thin film formed as a result of the alteration of the mineral, for example, under exposure to oxygen. The film often produces an iridescent effect. Tarnish is typical of bornite, chalcopyrite, limonite, and other minerals. It is not observed on a fresh surface of mineral breakage.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

tarnish

An oxide layer on a metal surface that causes it to dull, often discoloring it.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
But equally Howard Kendall doesn't deserve to have his memory tarnished in any way either.
Western culture should not be given recognition in India because this will tarnish our culture, tradition, and society.
Northern Province Bar Association's Vavuniya Branch Secretary Anton Punidnayagama said they would continue the boycott until legal action was taken against the miscreants responsible for the defamatory propaganda that tarnished the judges' reputation.
Copper pans tarnish because the copper combines with oxygen in air to form copper oxide, which is brown.
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The culture of spreading lies against people, especially government officials by members of the same government in order for them to tarnish political image of their colleagues, as part of attempt to secure jobs for either their relatives or friends", said Maya.
Adel Abdulla from the National Unity Assembly (NUA) called that in the past some people used the Kingdom sources as well as taking part at international conference to tarnish the image of the Kingdom of Bahrain, calling to use right people for the right place at various domains.
On Saturday, Mladenov told the Bulgarian National Radio, BNR, the Parliament must commit to a position on the issue, otherwise it would continue to tarnish the already tarnished enough image of the country, adding the Members of the Parliament should hold a debate and then publish an official declaration.
One of the reasons gold is so valued as a precious metal is that it does not tarnish, corrode, or otherwise deteriorate with time, being nonreactive towards air, moisture and most common oxidative reagents.
to tarnish the party's image, the leftist Beirut daily AS SAFIR reported Friday.
The transparent plastic material is impregnated with patented chemical formulations which absorb corrosive gases in the surrounding atmosphere and thereby protects silver, copper and electronic components from damage caused by oxidation, tarnish and corrosion.