Crystal Effect IHC's

With all the discussion on 'woodies', or Lincolns up to the 30'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. In my work I spend a lot of time looking at rocks, and looking at some of my IHC's made me think immediately of a crystal matrix common in a coarsely granuline rock such as a granite.

Example from a 1894 repunched date (Snow-1):







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). 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. This has the effect of making the metal more brittle, which is counter to the desired result.

However, I am not a metallurgist and would welcome other opinions as to the cause of the patterns I show here.

A beautiful example from a 1898:





If anyone has some examples in their collection, post pics!

 

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Very interesting, never seen that before !!!! I'll have to dig some out and take a look at mine. Thats a nice 94 also, re-punched date?

 

Whoa, niiice! I haven't seen it before either, sweet! :thumb:

Phoenix

 

That's an odd looking toning for an IHC. My first thought was alloy mixture/woodgrain, but on close inspection I'm not so sure. However, you do sometimes see a similar pattern on matron head large cents -- albeit with not quite as fine of a texture.

Regardless, thanks for sharing...Mike

 

Very interesting!!!
Nice observation.
I join the group who's never seen or even known about it.

About the cause.
I thought only dies were annealed.
Are planchets annealed too?

I agree with this much.
The more slowly a heated object cools, the more time the atoms/molecules have to arrange themselves resulting in visible crystals.

If only the dies are annealed, then they would have transferred the pattern to the coin during striking.
And I would think that would only occur early in die life and be "rubbed out" as the dies were used and worn.

If planchets are annealed, then this pattern could occur at any stage of die life.

I've only got a few IHC's, so it's unlikely that I have such a coin.
I'm going to a coin show tomorrow and MFD is a small cent specialist.
I'll run this by him.

 

Interesting thread! Acanthite's theory that is was caused by an annealing process applied to the planchets certainly seems plausible. Beautiful coins... however they came about.

Andy

 

Thanks, Kanga, for the offer to ask a cent specialist. In response to your question, the blanks are annealed to make planchets, and also the planchets are annealed before striking, according to the Cherrypicker's Guide.

It perhaps is a plausible theory only if it is realistic that the crystals would grow so large. If the largest they would ever grow is a few more microns than normal, then it would not account for what I show in the pictures.

 

I will have to check when I get home. I do see to recall seeing a couple that look like this in my collection.

 

The only time dies are annealed is to soften them for the hubbing process, They are hardened, not annealed, before striking coins. Planchets are annealed before striking. (I've noticed several people seem to use the terms anneal and harden interchangeably and they are actually opposites.)

 

Great picture of the 1894/4.

 

Well nothing like this, but several patterns. I attached anyway.

 

Thanks for the pics. Those examples look more like the classic 'woodgrain' texture, or perhaps somewhere in between the two. I have a few like that as well. Here is a closeup of a 1906 MPD.

 

That is a strange occurance, to say the least, acanthite. I'll have to break out my IHC's and see what I have. Can't say I've ever seen anything like it. I've seen manganese do that under extreme pressure from heat and cooling fluctuations in railway frogs, which leads to failure and breaking. Maybe the same effect can occur in other metals as well.
Guy~

 

I find it very interesting that the same material could be arranged in a flow pattern with straight lines across the entire diameter of the coin as well as in a crystalline patchwork pattern.

 

Talked to MFD yesterday about this.
He's a upper level small cent specialist.

He said most likely it's caused by one of two things:
1. During the annealling of the dies the crystalization occurs, and then the pattern is transferred during striking. Same as any other part of the design elements on the dies.
2. Someone has fiddled with the coins.

He further said that without the coin in hand he couldn't make a definitive analysis.

 

Thanks for asking, I appreciate your interest. I'm intrigued now, I will definitely bring them to the next show I go to. Rick Snow is scheduled to be there, perhaps I can get a moment of his time. I would be suprised if the 1894 had been fiddled with, as it is in an NGC holder. Nevertheless, it would be good to know.

 

If I recall correctly, Snow wrote THE book about Lincolns.
Don't know if he did IHCs or not.
Good source person for this sort of info.

 

Rick Snow is THE expert when it comes to Flying Eagle and Indian Head Cents. He wrote the multi-volume series The Flying Eagle And Indian Head Cent Attribution Guide. He is the founder of the Fly-In Club (for collectors of Flying Eagle & Indian Head Cents. His coin business is called Eagle Eye Rare Coins, specializing in (surprise, surprise) Flying Eagle and Indian Head Cents. His web site is www.indiancent.com.

What Lincoln book did Rick Snow write? I didn't know he was into Lincolns.

 

Well, I almost had it correct.
Right face value, wrong series.
:smile

 

Yeah, that happens to us all. What's that old saying? The first thing to go is your memory?

I'm off to a coin show. (If I can remember where it is.)

Now where did I put my car keys?