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<p>[QUOTE=&quot;acanthite, post: 364049, member: 6647&quot;]With all the discussion on &#039;woodies&#039;, or Lincolns up to the 30&#039;s with the streaked, woodgrain look from improper alloy mixing, made me go back and photograph another interesting metallurgical quandary in the Indian Head cents.&nbsp; In my work I spend a lot of time looking at rocks, and looking at some of my IHC&#039;s made me think immediately of a crystal matrix common in a coarsely granuline rock such as a granite.</p><p>&nbsp;</p><p>Example from a 1894 repunched date (Snow-1):</p><p>&nbsp;</p><p><img src="http://i182.photobucket.com/albums/x7/karakorum_photos/1c_1894over894-obv-red.jpg" class="bbCodeImage wysiwygImage" alt="" unselectable="on" /></p><p>&nbsp;</p><p><img src="http://i182.photobucket.com/albums/x7/karakorum_photos/1c_1894over894-detailxls2.jpg" class="bbCodeImage wysiwygImage" alt="" unselectable="on" /></p><p>&nbsp;</p><p><img src="http://i182.photobucket.com/albums/x7/karakorum_photos/1c_1894over894-detailxls3.jpg" class="bbCodeImage wysiwygImage" alt="" unselectable="on" /></p><p>&nbsp;</p><p>After doing some research I decided that in this case perhaps improper alloy mixing is not an explanation, but rather a prolonged annealing process (annealing in this case is heating planchets to soften them for striking).&nbsp; To put it simply, with copper-zinc-tin alloys, if the annealing process extends to long into the recrystallization phase, the metal crystals can grow larger than normal.&nbsp; This has the effect of making the metal more brittle, which is counter to the desired result.</p><p>&nbsp;</p><p><b>However, I am not a metallurgist and would welcome other opinions as to the cause of the patterns I show here.</b></p><p>&nbsp;</p><p>A beautiful example from a 1898:</p><p>&nbsp;</p><p><img src="http://i182.photobucket.com/albums/x7/karakorum_photos/1c_1898_AU-obv-red.jpg" class="bbCodeImage wysiwygImage" alt="" unselectable="on" /></p><p>&nbsp;</p><p><img src="http://i182.photobucket.com/albums/x7/karakorum_photos/1c_1898_AU-detailxls1-red-1.jpg" class="bbCodeImage wysiwygImage" alt="" unselectable="on" /></p><p>&nbsp;</p><p>If anyone has some examples in their collection, post pics![/QUOTE]</p><p><br /></p>

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