Early vs. Late Die State: Evaluating the Strike on 1868 Aluminum Proof Sets — A Die Variety Specialist’s Perspective

A coin struck from a fresh die looks nothing like one pulled from a dying one. The detail contrast alone is staggering. Let me walk you through the die progression on one of the most fascinating chapters in Mint history.

I’ve spent the better part of my career studying the subtle — and sometimes not-so-subtle — ways dies evolve over their working lives. The 1868 aluminum proof sets represent a case study that keeps pulling me back. They sit right at the intersection of experimental metallurgy, prestige Mint production, and the unforgiving mechanical realities of die life. When you examine these extraordinary pieces through the lens of die states, clash marks, weak strikes, die deterioration, and repolishing, a far richer story emerges than any catalog description could ever capture.

The Historical Context: Why Aluminum in 1868?

To make sense of the die varieties we observe on these sets, we first need to understand why the Mint was striking coins in aluminum at all. This wasn’t casual experimentation. By 1867, Mint officers recognized that aluminum — while the most abundant metal in the Earth’s crust — was extraordinarily difficult to isolate in pure form. Their real interest wasn’t aluminum coinage per se. They were exploring aluminum-based alloys for minor coinage that would hold up to circulation wear. Alloy experiments continued into the 1890s, but nothing involving aluminum ever proved superior to existing compositions.

Records from the Chief Coiner’s journal tell a revealing story. The Mint purchased 50 ounces of aluminum at $100 — roughly $2 per ounce — from a supplier named Victor Bishop. That was enough material to produce all nine sets with metal to spare. For context, the presentation cases cost $36 apiece, and John Jay Knox’s two sets had cases invoiced at $7 each. The total number of sets produced was likely around 15, though surviving records confirm at least 11.

By 1868, aluminum had dropped significantly from its earlier peak. Historical price data shows it trading at roughly $15 USD per pound in Europe in 1867 and $9 per pound in the USA by 1872. My own calculations suggest aluminum would have needed to be worth about $17 per Troy pound for the 1867 pattern nickels to contain five cents’ worth of aluminum — which was, after all, one of the original motivations for considering the metal in the first place. While no longer “more expensive than gold” as some collectors assume, aluminum was still exotic and scarce enough to make these sets genuine prestige objects with real numismatic value.

The 1868 Aluminum Cent: A Die Variety Case Study

The most thoroughly documented die variety story within the 1868 aluminum set involves the cent. As one specialist noted in a forum discussion, there are eight known examples of the aluminum 1868 cent, representing two die pairs — four of each. That’s a remarkably small population, and the identification of a ninth specimen would be genuinely significant because it would help establish which die pair was used first.

Identifying Die Pairs on the 1868 Aluminum Cent

When I examine these cents, I’m looking for several key markers to distinguish the two die pairs:

• Date positioning and repunching: Even minute shifts in digit placement or evidence of repunching can distinguish one die from another. On proof dies, repunching is relatively uncommon but not unheard of, particularly when a die setter noticed a weak initial impression.
• Die polish lines: Fresh dies often show characteristic polish lines from the lathe finishing process. These appear as fine, parallel striations on the coin’s fields and can be remarkably diagnostic when comparing early and late die states.
• Liberty’s portrait details: Subtle differences in the ribbon, the shield, or the positioning of lettering around the obverse rim can confirm die identity.

The fact that exactly four examples exist of each die pair points to a deliberate rotation. The Mint likely used one die pair until it showed signs of wear, then swapped to the second pair. This is entirely consistent with how the Mint managed proof die production in the 1860s, and it gives us a framework for understanding the entire striking sequence.

Die States and the Progression from Fresh to Worn

One of the most critical skills in die variety work is recognizing where a coin falls within the die’s lifespan. The 1868 aluminum proof sets — struck from regular dies, not specially prepared pattern dies — offer an excellent opportunity to study this progression in detail.

Early Die State (EDS) Characteristics

Coins struck from fresh dies exhibit unmistakable characteristics:

• Full, sharp detail: Every design element is crisply rendered, from the individual leaves in Liberty’s hair to the fine shield lines on the reverse.
• Mirror-like fields: Proof fields should be deeply reflective with minimal disturbance. Any roughness, granularity, or dullness in the field raises an immediate red flag for either die deterioration or suboptimal striking pressure.
• Sharp device-to-field junctions: The boundary where a raised design element meets the flat field should be razor-sharp. Rounding at these junctions is one of the earliest signs of die wear.
• Visible die polish lines: As I mentioned above, EDS coins often retain fine polish lines that become progressively obliterated as the die wears down.

When I encounter a genuine EDS example of the 1868 aluminum set, the eye appeal is immediately apparent. The luster is alive in a way that later states simply cannot replicate.

Mid Die State (MDS) Characteristics

As a die approaches the midpoint of its useful life, we begin to see subtle but telling changes:

• Slight softening of high points: The highest-relief elements — Liberty’s cheekbone, the shield’s central cross — may show minute flattening.
• Emergence of flow lines: Metal flow lines become more pronounced around the rim and devices as the die’s surface begins to erode microscopically.
• Early clash mark evidence: If the dies clashed (struck each other without a planchet between them), ghost impressions of the opposing design begin to appear. On aluminum pieces, clash marks can be particularly dramatic because aluminum is a softer metal that records die surface imperfections with extraordinary fidelity.

These mid-state pieces are where the real detective work begins. The collectibility of a well-documented MDS specimen can rival that of an EDS coin, especially if the clash evidence is dramatic and well-preserved.

Late Die State (LDS) Characteristics

By the time a die is nearing the end of its working life, several telltale signs emerge — and they can’t be ignored:

• Significant detail loss: Fine design elements begin to merge or disappear entirely. On cents, individual wheat stalks may blur together; on higher denominations, star points may become rounded and indistinct.
• Die deterioration doubling (DDD): This is one of the most commonly misidentified phenomena in numismatics. As the die develops microscopic cracks and erosion around design elements, a secondary, distorted image appears. This is not a repunched mintmark or intentional doubling — it’s a sign of a failing die.
• Pitting and roughness: The die surface develops tiny pits that transfer as raised bumps on the struck coin. These are most visible in the fields and can give the coin a granular, sandblasted appearance.
• Weak strikes: Paradoxically, a worn die can sometimes produce a weaker strike because the eroded surface no longer grips the planchet as effectively during the striking process.

LDS coins have their own kind of numismatic value for the variety specialist. They document the end of a die’s productive life and can help establish striking sequences that would otherwise remain unknown.

Clash Marks: Reading the Evidence of Die Contact

Clash marks are among the most informative — and most frequently misunderstood — features in die variety analysis. When the Mint’s presses operated without a planchet properly seated between the dies, the obverse and reverse dies would strike each other directly, transferring impressions of each design onto the opposing die.

For the 1868 aluminum proof sets, clash mark analysis is complicated by the small number of surviving specimens and the fact that these were proof strikes made under carefully controlled conditions. Still, I’ve identified several categories of clash evidence that collectors and researchers should watch for:

1. Obverse-to-reverse clash: Elements of the obverse design (Liberty, date, lettering) appear as incuse impressions on the reverse die, which then transfers them as raised features on subsequently struck coins.
2. Reverse-to-obverse clash: The reverse design (shield, denomination) appears on the obverse die.
3. Severe clash episodes: Multiple clash events can create a layered, almost ghostly appearance on the die surface, with overlapping impressions that are difficult to disentangle.

On aluminum specimens, clash marks tend to be more visually striking than on copper or silver coins. Aluminum’s softness allows it to fill even the shallowest die imperfections. This makes clash marks an especially valuable diagnostic tool for identifying die states within the 1868 aluminum series — and a key factor in assessing both provenance and eye appeal.

Weak Strikes and Their Relationship to Die Condition

Weak strikes on the 1868 aluminum proof sets can arise from several causes, and distinguishing between them is essential for accurate grading and valuation:

• Insufficient striking pressure: The press operator may not have applied full pressure. This was more common on experimental issues where the Mint was still calibrating its processes for an unfamiliar metal.
• Die deterioration: As I noted above, a worn die may not grip the planchet effectively, resulting in incomplete metal flow into the deepest recesses of the design.
• Planchet quality: Aluminum planchets were hand-prepared for these sets, and variations in blank diameter, thickness, or surface quality could affect the final strike.
• Die alignment: Slight misalignment between the obverse and reverse dies can produce an asymmetric strike where one side appears sharper than the other.

In my experience grading these pieces, weak strikes attributable to die deterioration are the most common, followed by planchet-related issues. True press-error weak strikes — where the die was in good condition but the press simply didn’t deliver full force — are rarer. Paradoxically, they can be more collectible because they represent a momentary production anomaly rather than a systemic die problem. That distinction matters enormously when you’re evaluating numismatic value.

Die Deterioration and Repolishing: The Mint’s Response

When the Mint’s die shop detected early signs of deterioration, the standard response was to repolish the die. This process involved removing a thin layer of metal from the die surface, effectively “resetting” the die to a condition closer to its original state. But repolishing is never a perfect fix:

• Loss of fine detail: Repolishing inevitably removes some design detail along with the damaged surface layer. A repolished die will produce coins that are sharper than those from the deteriorated die but slightly less crisp than those from the original, unpolished die.
• Altered surface texture: The repolished area will have a different surface texture than the surrounding unpolished areas. On the coin, this can appear as a slightly different luster or reflectivity in the affected region.
• Evidence of prior use: Even after repolishing, traces of clash marks, flow lines, or other evidence of the die’s earlier life may persist in areas that couldn’t be fully polished away.

For the 1868 aluminum proof sets, evidence of repolishing would be significant. It would suggest that the Mint was actively managing die condition during the production run — entirely consistent with the small, carefully controlled nature of the striking operation. Finding repolish evidence on one of these pieces would immediately elevate its collectibility for the variety specialist.

The Broader Pattern Context: 1855 to 1868

The 1868 aluminum proof sets didn’t emerge in a vacuum. They were part of a longer tradition of aluminum pattern and experimental coinage that began with the unique 1855 Seated Half Dollar in aluminum — a coin that remains something of a mystery. As one forum contributor noted, that piece may have been struck in connection with the 1855 Exposition Universelle in Paris, where Henri Sainte-Claire Deville’s breakthrough aluminum production process was displayed to enormous public interest.

Between 1855 and 1868, the Mint produced aluminum patterns sporadically:

• 1855: Unique aluminum Seated Half Dollar
• 1863: Postage currency dimes in aluminum
• 1864-L: Indian Head cent in aluminum (likely struck after 1867)
• 1867: 200 aluminum pattern nickels (Longacre patterns, not Shield Nickels)
• 1868: Complete aluminum proof sets (cent through double eagle)

Each of these issues used different dies and different production methods, but the underlying metallurgical motivation was consistent: the Mint was exploring whether aluminum or aluminum alloys could provide a durable, cost-effective alternative for minor coinage. Tracking the die varieties across this entire arc gives us a richer understanding of the Mint’s experimental processes over more than a decade.

Market Observations and Collectibility

The 1868 aluminum proof sets have appeared at auction with some regularity over the past two decades. Heritage has handled multiple sets, including the Newcomer/Garrett set (sold in 1997 and again in 2007), the Eric Newman set, and others. One forum contributor noted that these sets “get flipped at auction with some frequency,” suggesting that they may be less impressive in hand than photographs convey — particularly when removed from their original cases and slabbed by third-party grading services.

This observation has real implications for die variety specialists. When a set is broken up and individual coins are slabbed, the contextual information provided by the original case and the set’s provenance is partially lost. For die variety work, this is a significant concern because:

• Set coherence: Coins from the same set should share die states and characteristics. Breaking up a set makes it harder to confirm die pair identities.
• Provenance tracking: The history of a set — who owned it, when it was sold, how it was stored — provides valuable context for interpreting die condition and surface quality.
• Comparative analysis: Having multiple coins from the same set allows direct comparison of die states across denominations, which can reveal production sequences and die usage patterns.

When you’re assessing the collectibility of an individual coin from one of these sets, provenance isn’t just a nice bonus. It’s foundational data for the variety specialist.

A Note on the Famous Composite Image

One amusing footnote from the forum discussion deserves mention. The most widely circulated image of the 1868 aluminum proof set — the one that appears first in most internet searches — is actually a composite. The current owner of the set purchased it through Heritage in 2007, delivered the coins and original case to photographer Mark Goodman in Portland, and Goodman photographed the coins and case separately before cropping and pasting the coin images into the case image. In the process, the obverse images of the silver dollar and half dollar were accidentally transposed, as careful observers have noted by comparing the drapery at the elbow and the rock behind Miss Liberty.

This is a cautionary tale for die variety specialists who rely on internet images for research. Always verify the source and authenticity of any image before using it for comparative analysis. A transposed obverse might seem like a minor thing, but when you’re trying to identify a rare variety, it can send you down the wrong path entirely.

Actionable Takeaways for Collectors and Researchers

For collectors and researchers interested in the die varieties of the 1868 aluminum proof sets, here’s what I’d recommend based on years of hands-on work with these pieces:

1. Examine coins in hand whenever possible. Photographs — especially composite or poorly lit ones — can obscure critical die variety details that are immediately visible under proper lighting.
2. Document die states carefully. Use the EDS/MDS/LDS framework and note specific markers: clash evidence, polish lines, flow lines, doubling, and surface pitting. Detailed notes today save headaches tomorrow.
3. Track provenance meticulously. Knowing which coins came from which set is essential for establishing die pair sequences. Don’t rely on memory — write it down.
4. Cross-reference with known die pairs. For the 1868 cent, the two documented die pairs provide a baseline for comparison. Any new discovery should be measured against both.
5. Beware of die deterioration doubling. DDD is frequently mistaken for intentional repunching or other intentional varieties. Learn to distinguish the characteristic “smeared” appearance of DDD from the crisp, offset appearance of genuine repunching.
6. Consider the metal. Aluminum’s softness means that die imperfections are recorded with exceptional fidelity. This is both an advantage (more detail to analyze) and a disadvantage (more surface damage from handling). Handle these pieces accordingly.

Conclusion

The 1868 aluminum proof sets occupy a unique position in American numismatic history. They aren’t patterns in the traditional sense — they were struck from regular dies, in a precious (or at least exotic) metal, for prestige and exhibition purposes. Yet they embody everything that makes die variety study compelling: small populations, carefully controlled production, and the mechanical drama of dies being born, working, wearing, and ultimately being retired.

For the die variety specialist, these sets offer a rare opportunity to study die progression in a context where nearly every variable — the metal, the dies, the striking conditions — was known and controlled. The two die pairs on the 1868 cent, the evidence of clash marks and die deterioration across the full range of denominations, and the Mint’s evolving understanding of aluminum as a coinage metal all contribute to a story that is richer and more complex than any catalog entry can convey.

Whether you’re a collector seeking to acquire one of these remarkable sets, a researcher working to document the die varieties, or simply a numismatist who appreciates the intersection of metallurgy and minting craft, the 1868 aluminum proof sets reward close examination. Look beyond the exotic metal and the prestige packaging. Look at the dies. They have a story to tell — and for those of us willing to listen, the details are extraordinary.

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