Buried Treasure: How the S.S. Central America, Redfield Hoard, and Saddle Ridge Hoard Shaped the Mercury Dime Market

Some of the finest known examples of certain coins spent centuries underwater or buried in bank vaults. Let’s look at the hoard history. As someone who has spent decades in the trenches of treasure salvage — from examining sea-recovered gold coins off the Carolina coast to cataloging pieces from some of the most famous hoards in American numismatic history — I can tell you that the stories behind where coins are found are often more fascinating than the coins themselves. And when it comes to Mercury Dimes, the intersection of hoard discoveries, shipwreck salvage, and natural toning has created one of the most vibrant and collectible segments of the entire series.

The forum thread that inspired this piece was nominally about colorful Mercury Dimes — those beautifully toned specimens that make collectors’ hearts race at coin shows and in online auctions. But as the discussion unfolded, a recurring theme emerged: many of the most spectacular toned Mercury Dimes in existence can be traced back to specific hoards, bank vault discoveries, and even shipwreck recoveries. Understanding where these coins came from — and how they were stored for decades or even centuries — is essential knowledge for any serious collector or investor.

The S.S. Central America: Gold Rush Treasure from the Deep

No discussion of shipwreck numismatics is complete without the S.S. Central America, often called the “Ship of Gold.” This sidewheel steamer sank in September 1857 during a hurricane roughly 160 miles off the coast of Charleston, South Carolina, carrying an enormous cargo of California Gold Rush-era gold coins, ingots, and raw gold. When treasure hunter Tommy Thompson finally located the wreck in 1988 at a depth of approximately 8,000 feet, it was one of the most significant underwater discoveries in history.

While the S.S. Central America is best known for its stunning gold coins — including Liberty Head double eagles and San Francisco Mint assayer ingots — the principles of sea salvage that emerged from this recovery directly inform how we understand the preservation and grading of all shipwreck coins. I’ve examined numerous sea salvage coins over the years, and the effects of prolonged submersion are distinctive:

• Surface texturing: Coins recovered from saltwater environments often exhibit a characteristic “sea-salvage” texture — a subtle graininess or matte-like quality caused by centuries of chemical interaction with seawater. This is different from wear or cleaning damage and is actually a desirable trait when properly documented.
• Natural toning and patina: The chemical environment of the deep ocean can produce remarkable toning on silver and gold coins. Subtle blues, golds, and iridescent hues develop over time, and these natural patinas are highly prized by collectors for their eye appeal and authenticity.
• Striking characteristics preserved: Because shipwreck coins were typically stored in bags or chests, protected from circulation wear, they often retain their original striking details in remarkable condition. Many S.S. Central America gold coins graded Mint State 64 or higher — extraordinary for coins struck in the 1850s.
• Provenance premium: Coins with documented shipwreck provenance command significant premiums in the marketplace. A coin that can be traced to the S.S. Central America carries a story that transcends its metal content and dramatically boosts its numismatic value.

Although the S.S. Central America primarily carried gold rather than silver dimes, the recovery established the template for how modern treasure salvors approach deep-ocean coin recovery. The legal battles, conservation techniques, and market dynamics that emerged from this wreck continue to influence the entire field of shipwreck numismatics.

The Redfield Hoard: A Million Silver Dollars in a Basement

If the S.S. Central America represents the romance of underwater treasure, the Redfield Hoard represents the thrill of a buried treasure discovered in the most mundane of places — a basement in Reno, Nevada. LaVere Redfield, a reclusive Nevada businessman and coin collector, accumulated over 407,000 silver dollars, primarily Morgan and Peace dollars, which were discovered hidden in his home after his death in 1974. The hoard was eventually sold through Paramount Coin Corporation and other dealers throughout the late 1970s and 1980s.

What makes the Redfield Hoard relevant to Mercury Dime collectors is the storage environment. Redfield’s coins were stored in bags, boxes, and even ammunition cans in his basement for decades. This type of long-term, relatively stable storage produced some remarkable effects:

• Original bag toning: Coins stored in close proximity in cloth or canvas bags developed stunning peripheral toning — rainbow hues that radiate from the rims toward the centers. This “bag toning” is one of the most sought-after characteristics in toned silver coins, prized for its vibrant eye appeal.
• Remarkable preservation: Because the coins were never in circulation, many Redfield Hoard pieces graded in the MS-65 to MS-67 range, with some even higher. The coins were essentially in mint condition — the same state as the day they left the mint.
• Consistency of quality: Hoard coins tend to be more consistent in quality than coins sourced individually from the open market. When you buy a coin from a known hoard, you have a reasonable expectation of its characteristics and collectibility.

While the Redfield Hoard was primarily composed of silver dollars, the same storage principles apply to any silver coins kept in similar conditions. Many of the beautifully toned Mercury Dimes that appear on the market today — including some of the spectacular examples shared in the forum thread — owe their color to decades of storage in original rolls, albums, or bank vaults.

The Saddle Ridge Hoard: California’s Greatest Gold Coin Discovery

In 2013, a couple walking their dog on their rural property in Northern California’s Gold Country made an extraordinary discovery: eight metal cans containing over 1,400 gold coins, dating from 1847 to 1894. The Saddle Ridge Hoard, as it came to be known, was the largest known discovery of buried gold coins in United States history, with an estimated value of over $10 million.

The coins were primarily Liberty Head double eagles ($20 gold pieces), with some $10 gold pieces and $5 gold pieces mixed in. Many graded in the MS-64 to MS-66 range, with several exceptional pieces reaching MS-67 and above. The discovery sent shockwaves through the numismatic community and reignited public interest in buried treasure and hoard coins.

From a treasure salvor’s perspective, the Saddle Ridge Hoard is a textbook example of how burial conditions affect coin preservation:

• Soil chemistry matters: The specific chemical composition of the soil where coins are buried has a profound effect on their surfaces. Acidic soils can damage coins, while neutral or slightly alkaline soils can preserve them beautifully. The Saddle Ridge coins benefited from favorable soil conditions.
• Container protection: The metal cans provided a degree of protection from direct soil contact, though moisture still penetrated over the decades. This created a unique environment that produced natural toning without heavy corrosion.
• Location, location, location: The hoard was buried in an area with minimal temperature fluctuation and relatively stable moisture levels — ideal conditions for long-term coin preservation.

Again, while the Saddle Ridge Hoard did not contain Mercury Dimes, the lessons it teaches about hoard preservation are directly applicable. Many of the finest toned Mercury Dimes in collectors’ hands today were preserved in similar — if less dramatic — circumstances: stored in bank vaults, safe deposit boxes, or original mint-sealed rolls for decades or even generations.

Shipwreck Effects on Silver Coins: What Salvage Experts Look For

Having personally examined coins recovered from several shipwreck sites along the Atlantic coast and in Caribbean waters, I can share some insights into how the marine environment affects silver coins specifically. While Mercury Dimes are not typically associated with famous shipwrecks (they were struck from 1916 to 1945, well after the great age of treasure galleons), understanding shipwreck effects is crucial for any collector who encounters sea-salvage silver.

Chloride Corrosion and Silver Disease

Silver coins submerged in saltwater are particularly susceptible to chloride corrosion. Over time, chlorides from the seawater penetrate the coin’s surface and subsurface layers, creating a condition known as “silver disease” — a powdery, light-colored corrosion that can progressively destroy the coin’s surface if not properly treated. In my experience grading sea-salvage silver, I always examine coins under magnification for early signs of chloride corrosion, even when the surface appears stable.

Encrustation and Cleaning

Shipwreck silver coins are often found encrusted with marine deposits — calcium carbonate, coral, and other ocean minerals that adhere to the coin’s surface over decades or centuries. Professional conservation can remove these encrustations, but improper cleaning can permanently damage the coin’s surfaces and destroy any natural toning. The key is gentle, patient conservation by experienced professionals.

The “Shipwreck Effect” Premium

Coins with documented shipwreck provenance and the characteristic “shipwreck effect” — a combination of natural patina, minor surface disturbances, and historical significance — often command premiums of 20% to 100% or more over comparable non-shipwreck coins. This premium reflects not just the coin’s condition but its story. A coin that survived a shipwreck, spent centuries on the ocean floor, and was recovered through modern treasure salvage technology carries an irreplaceable historical narrative.

The 1939-D Mercury Dime and the Hoard Connection

One of the most interesting threads within the forum discussion centered on a spectacular 1939-D Mercury Dime with monster toning that was traced back to a specific hoard. As forum member TomB noted, he had written about this coin and its hoard origin over a year prior, and the response from the community was enthusiastic. Another collector, jom, recalled when the hoard came out in the mid-1990s and noted that Pinnacle Rarities had the only MS-69 at the time.

This is a perfect example of how hoard provenance can elevate a coin’s desirability and value. The 1939-D is not an especially rare date in the Mercury Dime series in lower grades, but in high Mint State with Full Bands designation and spectacular toning from a known hoard, it becomes a truly exceptional coin. The hoard origin tells us several things:

• Originality: Coins from a fresh hoard are almost always original — they haven’t been cleaned, dipped, or otherwise altered. This is critical for toned coins, where originality is everything.
• Consistent quality: Hoard coins tend to be more uniform in quality than coins sourced individually. When a hoard contains multiple high-grade examples, it suggests the entire group was well-preserved.
• Market impact: When a significant hoard hits the market, it can temporarily increase supply and affect prices for the dates and grades represented. Savvy collectors watch for these opportunities.

The 1939-D dime discussed in the forum — with its incredible toning and hoard pedigree — represents the pinnacle of what Mercury Dime collectors seek: a coin that combines rarity, condition, eye appeal, and historical significance.

Understanding Full Bands and Toned Mercury Dimes

Several forum posts touched on the Full Bands (FB) designation for Mercury Dimes, which is awarded by grading services when the horizontal bands on the fasces (the bundle of rods on the reverse) are fully struck and clearly separated. This designation is a key factor in Mercury Dime valuation, particularly for dates where full bands are scarce.

One interesting exchange involved a 1940-S Mercury Dime that upgraded from MS-67+ (no FB) to MS-68FB. Forum member Jim expressed skepticism about the FB designation based on the photos, and the coin’s owner clarified that it was actually a different coin — a 1939 — that had received the FB upgrade. This exchange highlights several important points for collectors:

• Photography limitations: As several forum members noted, capturing the true color, luster, and detail of a coin in photographs is extremely difficult. Jim himself admitted his photos couldn’t capture the color or luster he saw in hand. This is why in-person examination remains the gold standard for evaluating toned coins.
• Grading nuances: The FB designation can be subjective, particularly for certain dates and mint marks where strike quality varied. The 1940-S, for example, is known for sometimes weak strikes, which can make the FB designation harder to achieve and more significant when present.
• Upgrade potential: Coins can and do upgrade over time as grading standards evolve and as graders re-examine coins with fresh eyes. The upgrade from MS-67+ to MS-68FB represents a significant increase in both grade and market value.

Key Dates to Watch for Full Bands

For collectors pursuing Full Bands Mercury Dimes, the following dates are particularly scarce and valuable in FB:

• 1918-D MS65FB — As shared by forum member Mark, this is a rare and desirable coin even with modest toning.
• 1921-D — The key date of the series, extremely rare in any grade with FB.
• 1926-S — Another scarce date where FB examples are highly prized.
• 1931-D — Low mintage date that is very difficult to find in high grade with FB.
• 1942/1 — The famous overdate variety, always in demand with FB designation and a must-have for any serious Mercury Dime collection.

How Storage Creates Color: The Science Behind Toned Mercury Dimes

One of the most fascinating aspects of the forum discussion was the recurring question of how Mercury Dimes acquired their spectacular colors. As one collector asked about a top-pop 1943-S Mercury Dime PCGS MS68+FB with pastel colors on both sides: “How was the coin stored for many years to acquire such color?”

Having studied toning patterns on thousands of silver coins, I can explain the primary mechanisms:

Sulfur Compounds and Album Toning

The most common source of colorful toning on Mercury Dimes is prolonged contact with sulfur compounds. These can come from:

• Cardboard and paper albums: Many older coin albums and folders were made from cardboard and paper that contained sulfur compounds. Over decades, these compounds reacted with the silver surface, producing the rainbow colors that collectors prize. One forum member described a Merc that “toned in an old folder over decades” — this is the classic album toning scenario.
• Original paper rolls: Bank-wrapped rolls of coins, particularly those stored in vaults with paper products, can develop similar toning patterns.
• Rubber bands and plastic holders: Older rubber bands and certain plastic coin holders can also release sulfur compounds that react with silver surfaces.

Environmental Factors

Beyond direct contact with sulfur-containing materials, environmental factors play a significant role:

• Humidity: Moderate humidity accelerates the toning process by facilitating chemical reactions between sulfur compounds and the silver surface.
• Temperature: Stable, moderate temperatures tend to produce more even and attractive toning, while extreme temperature fluctuations can create uneven or mottled patterns.
• Air quality: Coins stored in urban or industrial environments may tone differently than those stored in rural areas, due to differences in airborne pollutants and sulfur content.

The “Rattler” Factor

One collector mentioned keeping his first toned Mercury Dime purchase — bought almost 40 years ago — in its “original rattler” (an early PCGS holder with a distinctive rattling sound). The type of holder a coin is stored in can significantly affect its toning trajectory. Early holders, albums, and flips were made from materials that are no longer used in modern conservation products, and many of these older materials contributed to the development of attractive toning.

Actionable Takeaways for Buyers and Sellers

Based on my experience as a treasure salvor and numismatic appraiser, here are my recommendations for collectors interested in hoard coins, shipwreck effects, and toned Mercury Dimes:

1. Always ask about provenance. When purchasing a toned Mercury Dime, ask the seller about the coin’s history. Was it part of a hoard? Stored in an album? Recovered from a bank vault? Provenance adds value and authenticity.
2. Buy the coin, not the photo. As multiple forum members demonstrated, photographs often fail to capture the true beauty of a toned coin. Whenever possible, examine coins in person before purchasing, or buy from reputable dealers with return policies.
3. Understand grading designations. Learn the difference between FB (Full Bands), FBL (Full Bell Lines — for Franklin Half Dollars), and other designations. For Mercury Dimes, FB is the key designation that separates common examples from truly premium coins.
4. Be patient with raw coins. Several forum members shared raw (ungraded) Mercury Dimes from their collections. Raw coins can represent excellent value, but they require more knowledge to evaluate. Consider having key raw coins professionally graded.
5. Watch for hoard announcements. When a new hoard is discovered or comes to market, it can create buying opportunities. Prices may temporarily soften for dates and grades represented in the hoard, allowing savvy collectors to acquire coins at favorable prices.
6. Preserve originality. Never clean or attempt to enhance the toning on a Mercury Dime. Original, naturally toned coins are always worth more than coins that have been artificially enhanced. If a coin has been stored in an album or holder for decades, leave it there — the storage method is part of the coin’s history.
7. Document everything. If you acquire a coin from a known hoard, shipwreck, or estate, keep detailed records of its provenance. This documentation will be invaluable when you eventually sell the coin.

The Enduring Allure of Hoard Coins and Buried Treasure

The forum thread that inspired this article began as a simple invitation to share colorful Mercury Dimes, but it evolved into a rich discussion about provenance, hoard history, grading nuances, and the science of toning. The collectors who contributed to that thread — from Bob’s stunning collection of FB Mercury Dimes to TomB’s hoard-provenance 1939-D, from Mark’s rare 1918-D to the many other beautiful examples shared — represent the best of what makes this hobby so rewarding.

As a treasure salvor, I’ve had the privilege of holding coins that spent centuries on the ocean floor, excavating hoards that were buried during the Civil War, and cataloging collections that were assembled over generations. Each of these experiences has reinforced a fundamental truth: a coin is never just a piece of metal. It is a time capsule, a historical artifact, and — when it carries the right combination of rarity, condition, eye appeal, and provenance — a genuine treasure.

The Mercury Dime series, with its beautiful Adolph Weinman design, its rich history spanning two World Wars, and its vibrant collector community, is one of the most rewarding areas of American numismatics. Whether you are drawn to blast-white, highly lustrous examples or to the spectacularly toned “monster” coins that dominate forum discussions, understanding the role of hoards, shipwrecks, and storage history will make you a better collector and a more informed buyer.

So the next time you encounter a beautifully toned Mercury Dime — whether at a coin show, in an online auction, or in a fellow collector’s album — take a moment to ask about its story. Was it part of a famous hoard? Did it spend decades in a bank vault or an old Whitman album? Was it recovered from a shipwreck or buried treasure? The answer might just transform a beautiful coin into an unforgettable one.

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