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The Ultimate Guide to 1966 Quarter Values

As a professional numismatist and lifelong collector of Washington quarters, I‘ve always found the coins struck in 1966 to be among the most fascinating and desirable issues in the entire series. This pivotal year marked a major transition in U.S. coinage, as the Mint switched from using valuable silver to more economical copper-nickel clad.

While this change made sense from a practical standpoint, it was controversial with collectors at the time who were used to the heft and beauty of the traditional 90% silver quarters. The public was also suspicious, with some claiming that a switch to "sandwich" metal quarters was a sign of the currency being debased.

Despite these misgivings, the new clad quarters would soon become the norm and are still being produced more than 50 years later. The 1966 issues represent the very first year of clad quarters and include some extremely rare and valuable error varieties. This guide will tell you everything you need to know to appreciate and collect these historic coins.

Key Facts About the 1966 Washington Quarter

  • Composition: Copper-nickel clad (91.67% copper, 8.33% nickel bonded to a pure copper core)
  • Diameter: 24.3 mm
  • Weight: 5.67 grams
  • Edge: Reeded
  • Mints: Philadelphia (no mintmark), Denver (no mintmark), San Francisco (special mint set only)
  • Total Mintage: 821,101,500 (includes 2,261,583 SMS coins)

The new clad quarters were struck to the same diameter as the earlier silver issues but were slightly thicker at 1.75 mm vs 1.65 mm due to the use of less dense copper and nickel. The reduction in weight and silver content was estimated to save the Treasury $30 million a year.

Visually, the untrained eye would be hard pressed to distinguish a 1966 clad quarter from the 1964 silver version. The Mint even went so far as to eliminate mintmarks on coins struck in 1965-1967 to discourage collecting and hoarding of the new issues. All quarters minted in 1966 lack a mintmark regardless of their origin.

Collecting Strategies and Key Varieties

For a collector interested in 1966 Washington quarters, there are a number of different directions to take. Many enjoy assembling a complete set of high-grade examples across the different strike types and varieties. Others focus more narrowly on individual rarities like errors, doubled dies, and transitional issues.

Here are some of the most popular ways to pursue 1966 quarters:

Regular-Issue Circulation Strikes

These are the coins struck for general circulation at the Philadelphia and Denver mints. Even in grades as high as MS67, regular 1966 quarters are highly affordable with prices of $75-150 in PCGS holders. Gems grading MS65 or MS66 can still be found in original uncirculated rolls.

Only at the very highest grades does the 1966 become a real condition rarity. The finest known is a single PCGS MS68+ that sold for $21,000 in 2008, followed by a dozen PCGS MS68s that have brought $1,500-4,400. Notably, no examples have been graded finer than MS67 by NGC.

Special Mint Set (SMS) Coins

For collectors seeking a premium quality option, the 1966 Special Mint Set coins are a great choice. Coined only at the San Francisco Mint, these special sets were produced as replacements for the traditional proof sets, which weren‘t struck in 1965 or 1966 due to the coinage transition.

While not quite as meticulously made as true proofs, the SMS coins still boast superior surfaces, strike, and eye appeal compared to regular issues. They were sold in limited quantities to collectors, with a total of 2,261,583 SMS sets ordered in 1966.

Today, the 1966 SMS quarters are prized by registry set collectors in high grades. Prices for SMS coins graded SP67 by PCGS range from $100 for a non-cameo piece up to $450 for a deep cameo. In the finest known SP68 grade, prices escalate to $1,000-3,000 for cameos and an impressive $5,000-7,000 for deep cameos.

Error Coins and Varieties

Perhaps the most exciting area for 1966 quarter collectors is the array of rare errors and die varieties known for the issue. With the chaotic switch from silver to clad, a number of fascinating (and valuable) mistakes occurred. Here are some of the most notable:

1966 Quarter Transitional Errors

  • Struck on Silver Planchet – The holy grail of 1966 errors would be a clad quarter accidentally struck on a leftover 90% silver planchet. While a few 1965 silver quarters are known, no confirmed 1966 examples have surfaced…yet.

  • Struck on Clad Dime Planchet – Several rare 1966 quarters have been discovered struck on dime-sized clad planchets, leaving a partial design as the dies were too large for the smaller blank. Only about a half dozen are known, with a PCGS MS64 example realizing $528 in a 2020 sale.

  • Struck on Cent, Nickel Planchets – Even rarer are off-metal errors on 1-cent and 5-cent planchets. A unique 1966 quarter on a clad nickel planchet, graded PCGS MS64, brought $402 in 2017. Meanwhile, a dramatic overstrike on a Philippine 25 centavos realized $5,170 in 2014.

Doubled Dies, Repunched Mintmarks, and Other Varieties

  • 1966 Doubled Die Reverse – This scarce variety shows clear doubling on the reverse legends and denomination. Cherrypickers‘ Guide FS-25c-1966-101 (039). Values range from $200 in XF40 to over $900 in Mint State.

  • 1966 RPM-001 – A repunched mintmark variety with a secondary D punch visible above the primary Denver D. FS-501 (FS-025.8). Priced at $40 in MS60 to $250 in MS65.

  • 1966 Quad Clip – This dramatic mint error features four curved clips around the edge of the coin due to a collar malfunction. One graded NGC MS64 sold for $1,116 in 2010.

Off-Center Strikes

Coins struck 5-10% or more off-center are popular with error collectors. A 1966 quarter with a 25% off-center strike realized $384 in a 2019 auction, while a dramatic 75% off-center on a clad dime clip (struck through cloth) soared to $1,410 in 2020.

Struck-Through Errors

From minor grease strikes to major struck-throughs covering much of the design, these errors occur when debris comes between a die and planchet during striking. A 1966 quarter with a large curved struck-through on Washington‘s head sold for $576 in a 2017 Heritage sale.

Suffice it to say, there is no shortage of rare and unusual varieties to keep a 1966 quarter specialist busy for years!

Grading and Pricing Guide

As with any series, the grade and relative rarity have a huge impact on the 1966 quarter values. Here is a quick guide to ballpark retail values for different strike types and grades:

Strike Type AG3 G4 VG8 F12 VF20 XF40 AU50 MS/SP60 MS/SP63 MS/SP65 MS/SP67 MS/SP68
Regular (P,D) $0.25 $0.25 $0.30 $0.35 $0.50 $1 $2 $5 $12 $25 $75 $1,500
SMS $20 $40 $100 $300 $3,000
Varieties* $50 $100 $200 $350 $500 $1,000 $2,500 $5,000

*Transitional errors and major varieties like doubled dies, off-metals, etc. Values are for PCGS or NGC certified coins only. Rare errors like off-center strikes or struck-throughs are valued on a case-by-case basis.

When buying any valuable 1966 quarter, I strongly recommend sticking with PCGS or NGC certified examples. These top-tier grading services have the expertise and experience to accurately authenticate rare varieties, and their plastic slabs offer peace of mind and liquidity.

Always check a seller‘s feedback and return policy before ordering, and watch out for doctored or counterfeit coins – especially supposed rarities in slabs that look too good to be true. If a deal seems to cheap, there‘s usually a reason!

Tips for Collectors

Whether you‘re a beginning collector or a seasoned pro, here are a few more tips to help you get the most out of 1966 Washington quarter collecting:

  • Look for original surfaces. Quarters with original, untampered-with surfaces are more desirable than those that have been cleaned, retoned, or otherwise altered. Telltale signs of cleaning include hairlines, a dull or lifeless appearance, or an unnatural color.

  • Focus on eye appeal. An attractive, problem-free coin with a sharp strike will be more desirable than a softly struck or unappealing piece even in the same technical grade. Eye appeal is king!

  • Consider a grading set. For regular issue quarters, try to assemble a "grading set" of the different circulated and Mint State grades so you can compare your raw coins and get a sense of their grade before purchase.

  • Check those rolls! You never know where a valuable variety or error coin might turn up. One collector I know found a 1966 transitional quarter struck on a clad dime planchet while searching rolls he bought from his local bank. Persistence can pay off.

  • Cherrypick "sliders." Sometimes, valuable error coins or varieties get overlooked and end up in discount bins, dealer junk boxes, or low-value eBay lots. Knowledge is power – a careful buyer who knows how to spot rarities can make some great discoveries with patience.

Final Thoughts

After more than five decades of clad coinage, many collectors are taking a new appreciative look at the quarters issued during the tumultuous transition away from silver. Chief among these are the first-year 1966 clad quarters – historic coins that capture the end of one era and the beginning of another.

Whether you‘re drawn to pristine SMS gems, unusual errors and varieties, or simply high-grade regular issues, the 1966 Washington quarter series offers a fascinating niche. Values are on the rise for exceptional pieces, and new varieties continue to be discovered by eagle-eyed collectors.

If you decide to take the plunge into this pivotal series, buy the best coins you can afford from reputable sources. Specialized references like the Cherrypickers‘ Guide and Mint Error News can greatly expand your knowledge. Above all, focus on coins that you find attractive and appealing – collect what you love!

Who knows? With a bit of perseverance, you just might find that next headline-making 1966 rarity. But even if you never hit the jackpot, you‘ll own an important piece of coinage history. And that‘s a priceless feeling indeed.