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<p>[QUOTE=&quot;survivor, post: 36292, member: 1474&quot;]<b>Enviromental Damage</b></p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p>I copied this from a site I was researching. </p><p><br /></p><p><br /></p><p>Copper is a very reactive metal, which oxidizes easily in the presence of moisture, he says.</p><p><br /></p><p>&quot;The problems can range from slight dullness of surface, a matte type of appearance, to very heavily pitted, corroded, foxhole type of problems … from slightly dull, to lightly grainy, to light even granularity, to scale and green deposits.&quot;</p><p><br /></p><p>Green or blue-green deposits are verdigris, a poisonous, acidic copper compound at the end of the oxidation process. The substance may be pronounced VERD-uh-grease, VERD-uh-griss or VERD-uh-gree, and it may start as a filmy, scummy coating or become a raised crust. Copper collectors refer to the latter form inelegantly as &quot;crud,&quot; and such a coin and even some lesser corrosion problem pieces as &quot;scudzy.&quot;</p><p><br /></p><p>An encrustation of verdigris can be removed carefully by an expert, arresting any advance, but a pit will be left where the corrosion ate below the surface of the coin.</p><p><br /></p><p>&quot;Porosity,&quot; strictly speaking, involves pitting.</p><p><br /></p><p>Jack Beymer, a dealer whose inventory is regularly strong in early U.S. copper, sees porosity as the effect of extreme oxidation but on a continuum that begins with simple, natural toning.</p><p><br /></p><p>&quot;Ultimately, it&#039;s the effect of the environment on the surface. You could term really heavy black toning a form of porosity,&quot; he says. &quot;It&#039;s oxidation. Extreme oxidation. Heavy craters? Obviously just porosity gone rampant. Light porosity is very light pitting.&quot;</p><p><br /></p><p>Julian Leidman, another dealer who regularly carries early U.S. copper, said: &quot;I would probably define [porosity] as irregular surfaces due to outside influences. You&#039;re going to have areas of coins with pitting, maybe from something lying on it, or it was in the dirt and something ate into it.&quot;</p><p><br /></p><p>The chief culprit in corrosion and pitting is moisture, Reynolds says. Copper is especially vulnerable if stored improperly and is additionally vulnerable in ocean climates and damp basements, he says.[/QUOTE]</p><p><br /></p>

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