Protecting Your 1870 Liberty Head Double Eagle: A Conservationist’s Guide

The Preservation Imperative

Too many valuable coins have been ruined by improper cleaning or storage. Here’s how to keep your 1870 Liberty Head double eagle safe for future generations.

Understanding Your 1870 Liberty Head Double Eagle

The 1870 Liberty Head $20 gold piece represents a fascinating chapter in American numismatics. Whether your specimen is from Philadelphia or the rare San Francisco mint, proper preservation is essential. The Liberty Head design, featuring Miss Liberty facing left with a coronet inscribed with “LIBERTY,” remained in production from 1849 to 1907, making it one of the most iconic American coin designs.

Historical Significance of the 1870 Issue

The 1870 double eagle holds particular interest for collectors. Philadelphia minted these coins in substantial numbers, while the San Francisco Mint produced far fewer, making the 1870-S a key date in the series. The die variations discussed in collector forums, including the position of the date relative to Liberty’s neck, reflect the hand-crafted nature of 19th-century minting processes. Each working die was individually prepared, resulting in subtle variations that today’s collectors find fascinating.

Identifying Key Markers

When examining your 1870 double eagle, several factors deserve attention. The date position variation is completely normal and results from the manual process of punching individual digits into working dies. Some specimens show the “1” touching Liberty’s neck, while others display more separation. This variation doesn’t affect authenticity or value significantly. The mint mark position (for 1870-S coins) also varies slightly between dies, with some showing a more refined “S” slightly right of center.

Authentication Considerations

Weight and diameter measurements provide initial authenticity checks. A genuine Liberty Head double eagle should weigh approximately 33.4 grams with a diameter of 34mm. However, these measurements alone cannot confirm authenticity, as counterfeits can match specifications. The coin’s overall appearance, strike quality, and surface characteristics require expert evaluation. The weak details mentioned by forum participants might indicate wear or possibly a counterfeit, though legitimate coins can show varying strike quality depending on die condition and striking pressure.

The Toning Question

Natural toning on gold coins develops slowly over decades, creating subtle color variations from deep yellow to reddish or greenish hues. This toning, while less dramatic than on silver coins, represents the coin’s history and should be preserved. Never attempt to remove toning or polish the surface, as this permanently damages the coin and significantly reduces its numismatic value. The warm, natural luster of an untouched gold coin is far more desirable to collectors than a bright, cleaned surface.

Oxidation and Environmental Factors

While gold itself doesn’t oxidize in the same way as silver or copper, the copper and silver alloyed with the gold can develop surface changes. Environmental factors including humidity, temperature fluctuations, and exposure to chemicals can affect even gold coins. The most significant threat comes from improper storage materials that can cause chemical reactions. Even minimal exposure to sulfur compounds in the air can gradually alter a coin’s surface appearance.

PVC Damage: The Silent Destroyer

Polyvinyl chloride (PVC) represents one of the most serious threats to coin preservation. Found in many older plastic flips, PVC can break down over time, releasing acidic gases that adhere to coin surfaces, creating a slimy green residue that permanently damages the coin. This damage is irreversible and significantly reduces a coin’s collectibility. Always examine your storage materials carefully and replace any that show signs of deterioration or that you suspect might contain PVC.

Proper Holders and Storage Solutions

Modern archival-quality holders provide the best protection for your 1870 double eagle. Look for materials labeled as PVC-free, acid-free, and inert. Mylar and polyester flips offer excellent protection while allowing you to view both sides of the coin. For higher-value specimens, rigid holders with gaskets provide superior protection against physical damage and environmental factors. Always store coins in a cool, dry environment away from direct sunlight and extreme temperature fluctuations.

To Clean or Not to Clean: The Golden Rule

Never clean valuable coins. This cannot be overstated. Cleaning removes the natural patina and microscopic details that develop over time, creating unnatural surfaces that collectors and dealers immediately recognize. Even gentle cleaning with mild soap and water can remove toning and create hairlines that significantly reduce a coin’s grade and value. If your coin has accumulated dirt or debris, consult a professional conservator rather than attempting any cleaning yourself.

Professional Conservation Options

For coins with significant environmental damage or residue, professional conservation services exist. These experts use specialized techniques to remove harmful deposits without damaging the coin’s surface. However, conservation should only be considered when absolutely necessary, as it may affect the coin’s originality and, in some cases, its market value. Always retain documentation of any conservation work performed.

Insurance and Documentation

Given the value of an 1870 Liberty Head double eagle, proper documentation and insurance are essential. Maintain detailed records including photographs, weight and measurement data, and any authentication certificates. Store these records separately from the coins themselves in a fireproof location. Consider specialized collectibles insurance that covers the full replacement value of your coins.

Long-term Preservation Strategy

Developing a comprehensive preservation strategy ensures your 1870 double eagle remains protected for future generations. This includes regular inspection for any signs of deterioration, maintaining stable storage conditions, using only archival-quality materials, and keeping the coin in its holder except when absolutely necessary to examine it. Remember that each time a coin is handled, there’s potential for damage from skin oils and accidental drops.

Conclusion: The Legacy of Preservation

Your 1870 Liberty Head double eagle represents more than just a monetary value—it’s a tangible piece of American history. By following proper preservation techniques, you ensure this historical artifact survives in excellent condition for future collectors and historians. The subtle variations in die characteristics, the natural toning that develops over time, and the coin’s overall state of preservation all contribute to its story and value. Whether your specimen shows the “1” touching Liberty’s neck or positioned further away, proper care will maintain its integrity as both a collectible and a historical object. The next generation of collectors will thank you for your conservation efforts.

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