1994-D Lincoln Memorial Cent / LMC Blue Doubling, How Is This Formed During Minting?

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Author	Replies: 11 / Views: 615
CentR Valued Member United States 139 Posts	Posted 12/31/2023 01:49 am Does anyone know how this common beautiful blue doubling is formed during minting? Is it in error or a variety? There are many examples online, so could it be a variety, or just a common printing error? Do these error/varieties have a specific name/classification? thanks, Mike Edited by CentR 12/31/2023 02:17 am Report this Post to the Staff

Errers and Varietys Bedrock of the Community United States 74138 Posts	Posted 12/31/2023 02:12 am That's just Split Plating. Very common on copper plated zinc cents. https://www.error-ref.com/split-plating/ Errers and Varietys. Report this Post to the Staff
lcutler Pillar of the Community United States 1657 Posts	Posted 12/31/2023 04:16 am Also, the beautiful blue will become zinc corrosion. Report this Post to the Staff
John1 Moderator United States 56855 Posts	Posted 12/31/2023 04:35 am CentR, Coins are minted not printed, just a FYI. The blue you see is the zinc core. Normally I would tell you that we do not like photos posted of scopes screens, but yours turned out well. John1 Report this Post to the Staff
ijn1944 Bedrock of the Community United States 19154 Posts	Posted 12/31/2023 07:12 am Yes, Die Deterioration issues and split plating. Exposed zinc core. Report this Post to the Staff
oddguy Pillar of the Community United States 4135 Posts	Posted 12/31/2023 09:11 am Agree with above and yes, very nice close up pictures. Report this Post to the Staff
Coinfrog Bedrock of the Community United States 94367 Posts	Posted 12/31/2023 11:12 am to the CCF! Report this Post to the Staff
CentR Valued Member United States 139 Posts	Posted 12/31/2023 2:33 pm Thank you for the amazingly detailed helpful responses and references! I like the look of this error and would like to preserve the most attractive part of the error to me, the raised bubbly bluish outlines. Then collect additional nice specimens. What I'm seeing in regards to zinc and copper chemistry suggests the raised bluish outlines may be due in part to an oxidized zinc copper (brass) compound formed under pressure of minting. It may not due to exposed zinc underneath, which would be silvery white. As described in the helpful reference provided by Errers and Varietys, whitish crystals will grow on top of the blue raised areas due to formation of Zn5(CO3)2(OH)6 over time. I'm thinking VERDI-CARE might keep these crystals from forming, or maybe just some olive oil wiped over the coin, and a good holder? Any suggestions on what might be best? Lastly, thanks for your graciousness and patience with someone that's just getting back into collecting after 40 years in a immunology lab (which explains the OCD microscope images). Mike Edited by CentR 12/31/2023 2:34 pm Report this Post to the Staff
silviosi Pillar of the Community Canada 6244 Posts	Posted 12/31/2023 2:46 pm Pay attention. VERDI-CARE it is not for Zinc. Quote: I'm thinking VERDI-CARE might keep these crystals from forming, or maybe just some olive oil wiped over the coin, and a good holder? Three thinks here: 1. Olive Oil in is acidic and will not inhibit the Zinc expassionist Oxide. 2. Good holder? Yes if you can vacuum. Do will be worth to do? 3. Any TPG or air tide caps could not be vacuum, will broke due to the differential in the pressions. The only it is in PET. I done such holders but the cost of wacuum, holders and process come to aprox 25 $. It is worth for valuable coins. After this, the conservation environement took place. You will need out of the UV and less then 50 EMF with an aprox stable temperature. My safe box for the valuable coins and notes to have constant temperature and humidity cost me over 2000 $. Think. Edited by silviosi 12/31/2023 8:27 pm Report this Post to the Staff
Dearborn Moderator United States 95936 Posts	Posted 12/31/2023 8:06 pm yes, EV and Ijn covered what happened here quite well. Collecting since 1972. Learning from then on "Tell me and I forget. Teach me and I remember. Involve me and I learn." - Benjamin Franklin 7070 type set coin count: 51/76 Uncirculated American Silver Eagles My American Silver Eagle Proof Collection Sacagawea Dollars Innovation Dollars Eisenhower-Dollars Kennedy-Half Dollars Washington-Quarters Roosevelt-Dimes Buffalo-Nickels 1938-2005 Jefferson-Nickels Lincoln-Cents Report this Post to the Staff
CentR Valued Member United States 139 Posts	Posted 12/31/2023 9:30 pm Thanks Silviosi for your comment noting the slight acidity of olive oil. Could be an ideal mildly reducing environment to inhibit zinc oxidation on these nearly valueless oddities. In case I wasn't clear, the idea of using VERDI-CARE is not for zinc. Zinc and zinc redox derivatives are not blue. The question was how to preserve the beautiful blue compound outlining the coin's features, which is likely a derivative of copper or brass (copper and zinc), both of which VERDI-CARE is designed for specifically. Report this Post to the Staff
silviosi Pillar of the Community Canada 6244 Posts	Posted 12/31/2023 10:08 pm This it is the olive oil acid: Oleic acid is the preponderant MUFA component (55.00-83.00%). Other fatty acids (FA) in olive oil are linoleic acid (2.50 to 21.00%), palmitic acid (7.50 to 20.00%), and α-linolenic acid (#8804;1.00%).Jul 8, 2021 So you has three kind of acids: MUFA, FA and alfa. Those are MUFA and FA mild acids and low acid alfa. Due to the fact that those metals in the cent are Cu oxigenated and the Zinc oxi hydro-oxigenated, on contact wwith those acids will eliberate the free anions and accelerate the oxidations. This it is the molecular explanation on very short for those non magnetic materials. those materials are very low EMF so the acids will react. You want to try? Go ahead and good luck and Happy New Year. Edited by silviosi 12/31/2023 10:32 pm Report this Post to the Staff
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1994-D LMC Blue Doubling, How Is This Formed During Minting?