A newly discovered letter by Philadelphia Mint Coiner A. Loudon Snowden adds to our knowledge of how proof-like coins were made.
While this new information introduces another layer of complexity into coin manufacture, it also helps explain the high proportion of proof-like coins – especially silver dollars – produced by mints at Carson and San Francisco during the 1880s.
What Is A “Proof-Like” Coin?
It is a regular circulation coin whose fields exhibit mirror-like reflectivity that superficially resembles intentionally mirrored fields of a proof coin, and it has visual contrast between the fields and the unpolished reflective relief. An alternative descriptive name for this is “mirror-like.”
Subjective factors, including the reflectivity of the fields and the contrast between the fields and the relief, further separate proof-like coins. It is possible to measure these factors objectively, but thus far, no authentication company has taken these simple steps.
The illustration above shows a typical high-quality 1881-S proof-like coin. If the fields had more pronounced mirror-like fields, it might be called a deep-mirror proof-like example.
Causes of Proof-Like Coins.
It had long been assumed, although without evidence, that the final step in manufacturing working dies was to polish the die face. It was believed this produced a weak to moderate mirror surface which then produced what are called proof-like coins.
Modern research into U.S. Mint archives by the present author and others has shown that the final step in die manufacture was a dip in weak acid to remove fire-scale and other oxidation products from the die.
Thus, new dies began their service with a smooth, very fine grained surface. This was quickly altered during use to a bright, lustrous surface which persisted for remaining life of the die.
Additional research (primarily with Morgan dollars) showed that a mirror-like reflective surface was often created incidental to die maintenance and rebasining.
What is “rebasining?
Routine maintenance involved gently polishing the raised field of a die to remove small cracks, scrapes, and clash marks. If a fine abrasive were used, the field would take on a mirror-like appearance.
Rebasining was a special situation where the convex curvature of a die deviated from its intended (or preferred) curvature. Correction required a more aggressive approach than ordinary maintenance.
A prepared disc of zinc, of the correct curvature, was coated with abrasive, and pressed against the defective die. This abraded away steel from the die face until it matched a template of the correct radius of curvature. The entire die face was then gently polished just as in ordinary maintenance, if needed. [1]
In all instances, the mirror-like field gradually fades as the die surface returns to its typical luster. [2]
A. Loudon Snowden’s Suggestions.
During the second half of 1875 the Carson Mint experienced serious problems with coining Trade Dollars. These denominated bullion pieces were intended to supplant Mexican silver peso coins long favored in Asian trading markets.
The coins, which were legal tender up to $5 in the United States, had to meet strict specifications before issue by the mints. But they also had to be approved by Asian merchant bankers, who accepted coins both by technical specifications and subjective visual criteria. [3]
On November 14 San Francisco Customs House, Treasury Special Agent J. F. Evans received a complaint from Wells Fargo & Co. that “they sold for shipment to China, a lot of Trade Dollars, and 6,000 of those coined at Carson City for the alleged reason that they were imperfect…and had to be sold at a discount of two percent.” [4]
The primary complaints were: “rough and imperfect in finish; want of distinctness in the figures on the coin; reeding not heavy enough; letters CC not quite of the same size; eagle’s head and wings have a mashed, battered look, and other impressions within the legends are blurred, giving coin an unfinished and rather shabby aspect.” [5]
Mint Director Henry R. Linderman asked several mint officers, including Philadelphia Mint Coiner Snowden for their comments. He sent a copy of Snowden’s, dated December 21, to Superintendent LaGrange at San Francisco.
The Snowden Letters
Snowden began by recommending sample coins, planchets and dies be sent to Philadelphia for examination.[6]
It would be much more satisfactory in deciding a question so important, and one affecting the work of another Mint, if we had in our possession for examination, both the unstruck planchets and the coined pieces, as well as the dies used in the coinage….
So that we might make an examination with the pieces, planchets and dies before us, for inspection and comparison, and I would respectfully recommend that this course be adopted.
Not having the planchets, coin or dies to examine, I must take it for granted that the defects named by Mr. Evans do exist, and treat them accordingly. [7]
He then listed and described twelve possible causes of the defects Evans described. The twelfth and final suggestion relates to die polishing.
Twelfth. Dies not polished. One want of brightness said to characterize the Carson Dollars, may to a great extent arise from the use of unpolished dies. Polished dies have only been used in our ordinary coinage within the past few years.
I found that the labor in keeping the dies polished was trifling, whilst the quality of the coinage was much enhanced. This work I specially commit to the foreman of the Coining Room.
Mr. Eckfeldt, late an officer in the Mint at San Francisco, noticed in one of his visits here [to Philadelphia Mint], that our coins were brighter than those coined at San Francisco and on learning the cause, said the plan should be adopted on his return, which I know was done. It is a very simple operation, and should not be omitted. [8]
Snowden does not explain what is meant by “polishing,” and we cannot tell if he was referring to use of a very fine abrasive, such as Vienna lime which could produce a proof-like reflective surface, or something coarser which might imitate bright luster.
Although the letter is not definitive, it opens the possibility that a large proportion of proof-like dollar-size coins struck at San Francisco and Carson Mints could have been made with pre-polished new dies.
As with any other historical research, there is often more remaining to be discovered.
by Roger W. Burdette
Copyright 2025. All rights reserved
Citations
[2] See: Roger W. Burdette. From Mine to Mint. Seneca Mill Press LLC, for additional information.
[3] Trade dollars were not coins, but simply convenient bullion pieces of uniform weight, purity and design. Asian merchant bankers inspected and marked each Trade dollar with an incuse stamp certifying their acceptance of the coin. Each banker used their own mark or “chop” and some coins might have a dozen or more chops.
[4] The coinage charge for Trade dollars was 1.25 percent, meaning that Wells, Fargo & Co. lost 0.75% on the Carson Mint coins.
[5] SB RG104 1.7 Box 6, 391-395, ARC 1656130. Letter dated November 30, 1875 to Solicitor of the Treasury from Evans. Quotation extracted from text.
[6] RG104 E-235 Vol 007. Letter dated December 28, 1875 to LaGrange from Linderman. Superintendent Crawford at Carson is assumed to have also been sent a copy.
[7] SB RG104 1.7 Box 6, 413-414. ARC 1656130. Letter dated December 21, 1875 to Pollock from Snowden.
[8] SB RG104 1.7 Box 6, 417-418. ARC 1656130. Letter dated December 21, 1875 to Pollock from Snowden.
If a proportion of the coins were made with pre-polished new dies do they still have a die marker or something to trace a coin back to a certain set of dies ? Would it be appropriate to call type one with the old dies and type two with the new dies ?