The 1970-S Washington Quarter is worth anywhere from $1 in proof condition to over $2,000 for rare high-grade specimens. While most found in pocket change are common, certain proof sets and errors carry a significant premium for everyday Americans looking to cash in on their spare change.

Condition / Grade	Estimated Value
Proof (PR-65)	$2.00 – $5.00
Deep Cameo (PR-69 DCAM)	$25.00 – $50.00
Mint State Error (MS-65)	$500.00+
The “1970 25c Over 1900 Canada”	$2,000.00 – $15,000.00

Identifying the 1970-S Washington Quarter

If you have found a 1970 quarter with an “S” mint mark, you are likely holding a proof coin. Unlike the quarters you spend at the grocery store, which were minted in Philadelphia or Denver, San Francisco exclusively produced proof versions for collectors this year. You can find out more about your find using a top coin identifier app to see if you have a standard proof or a rare error.

The “S” mint mark is located on the obverse side of the coin, just to the right of George Washington’s ponytail. These coins were originally sold in plastic-encased sets. If your 1970-S quarter looks shiny, mirrored, or exceptionally detailed, it likely came from one of these sets.

For beginners, the most important tool is the CoinKnow app, which helps you distinguish between common circulation wear and high-value proof finishes. Knowing the difference is the first step in determining if your 1970-S Washington quarter is worth more than its face value.

Why the 1970-S Quarter Is Unique

In 1970, the U.S. Mint produced over 2.6 million proof quarters at the San Francisco facility. This was an era of transition for American coinage, moving away from silver and into the “clad” composition we use today. The 1970-S Washington quarter is made of a copper-nickel alloy over a pure copper core.

Because these were intended for collectors, they usually have much better preservation than “P” or “D” mint quarters. However, tens of thousands of these sets have been broken open over the decades. This leads to proof quarters being found in general circulation, where they might look slightly “foggier” than a new quarter.

When checking current 1970 Washington quarter market prices, you will notice that the grade makes all the difference. A simple scratch or an “unfocused” strike can drop the value from fifty dollars to just fifty cents in seconds.

The Rare 1970-S Overstrike Error

The holy grail for anyone searching through 1970-S Washington quarters is the famous overstrike error. In an incredible minting fluke, some 1970-S quarters were struck over 1900-era Canadian quarters. If you look closely at these coins, you can see faint outlines of the Canadian design underneath Washington’s portrait.

These specific errors are incredibly rare and have sold at auction for over $35,000 in extreme cases. Most collectors will never see one in person, but it is the reason why the 1970-S is so famous in the hobby. If you suspect your coin has strange markings or “double” features, using CoinKnow to zoom in on the details is a great way to start your investigation.

A genuine error of this magnitude is the reason why people still hunt through old coin jars fifty years later. For a deep dive into these types of anomalies, you should check this 1970 quarter value guide to compare your coin against known genuine errors.

Error Type	Visual Sign	Potential Value
Struck over 1900 Canada 25c	Faint Canadian text or dates	$5,000 – $15,000+
Double Die Obverse	Doubling in “In God We Trust”	$50 – $200
Off-Center Strike	Missing edge or lopsided design	$20 – $100

Determining the Grade of Your 1970-S Quarter

Coin grading is the process of determining how much wear a coin has. For the 1970-S Washington quarter, grading is usually done on the “Proof” (PR) scale. A PR-70 is a perfect coin with no flaws visible under 5x magnification. Most coins found in original sets are PR-65 to PR-68.

One highly sought-after feature is the “Cameo” (CAM) or “Deep Cameo” (DCAM) effect. This occurs when the portrait of Washington is frosty and matte-white, while the surrounding background (the field) is shiny like a black mirror. Deep Cameo 1970-S quarters are significantly more valuable than those where the whole coin is just shiny.

If your coin has been floating in a pocket for years, it may be graded as “Impaired Proof.” These are only worth about $1.00. However, if you keep your quarters in protective flips, you preserve their potential for high-end collectors. Using the CoinKnow app can help you photograph your coin at the right angle to see if that “frosty” cameo effect resides on your specimen.

Where to Sell Your 1970-S Washington Quarter

Once you realize you have a high-grade or error coin, the next question is where to sell it. For coins worth less than $20, platforms like eBay or local coin shops are your best bet. Collectors often browse eBay for specific DCAM (Deep Cameo) grades to complete their year-run albums.

For massive errors like the Canadian overstrike, you should contact a professional auction house like Heritage Auctions or Stack’s Bowers. These high-value items require third-party certification from services like PCGS or NGC before they can be sold for thousands of dollars.

Never clean your coins before selling them. Many beginners think that scrubbing a 1970-S quarter with soap or metal polish will make it look “more like a proof,” but this actually destroys the value. Collectors prefer natural toning or even light scratches over a coin that has been chemically cleaned.

Sales Outlet	Best for…	Fees/Time
eBay	Standard Proofs ($2-$20)	~13% / Quick
Local Coin Shop	Bulk sales or quick cash	Low payout / Instant
Major Auction House	Rare Errors ($1,000+)	20% / Months

FAQ

Q: Is the 1970-S Washington Quarter made of silver?

A: No, the 1970-S Washington quarter is not made of silver. It is a “clad” coin consisting of 75% copper and 25% nickel. The last business-strike silver quarters were made in 1964.

Q: How can I tell if I have the rare Canadian overstrike?

A: You will need a magnifying glass. Look at the reverse side for tiny ghosts of a crown or the date “1900.” On the obverse, look for extra lettering around Washington’s head that doesn’t belong on a U.S. coin.

Q: Why is my 1970 quarter not shiny if it has an “S” mark?

A: You likely have an “impaired proof.” This means the coin was spent at some point and the mirrored surface was worn away by other coins. It is still a 1970-S, but its value is much lower than a pristine version.

Q: Can I find a 1970-S quarter in my pocket change?

A: It is possible, but rare. Since they were only sold in sets, a 1970-S only ends up in circulation if someone accidentally spends a proof set or if a collection was stolen and spent.

Q: What is the most expensive 1970-S quarter ever sold?

A: The record is held by a 1970-S quarter struck over a 1900 Barber Quarter, which sold for over $35,000. Most high-grade 1970-S DCAM coins sell for around $30 to $100.