1999-S Pennsylvania State Quarter Value: Is It Worth Money?

The 1999-S Pennsylvania State Quarter is worth anywhere from $0.50 in typical proof condition to over $1,200 for rare, high-grade Silver Deep Cameo specimens. While your pocket change version is likely worth more than its 25-cent face value, specific “S” mint marks hold the highest potential for collectors and everyday treasure hunters.

Condition/Type	Estimated Value
Clad Proof (S Mint Mark)	$2.00 – $10.00
Silver Proof (S Mint Mark)	$25.00 – $85.00
High Grade PR70 Silver	$500.00 – $1,200.00+

Identifying Your 1999-S Pennsylvania Quarter

Finding a collectible quarter starts with identifying the “S” mint mark. Unlike the common Philly or Denver quarters you find at the grocery store, the “S” indicates the coin was struck at the San Francisco Mint. These were specifically produced for collectors and were never intended to enter general circulation. If you find one in your change, someone likely broke open a proof set to spend it! To get an instant identification and grade, many hobbyists use a top coin identifier app to see if they have found something rare.

The Pennsylvania quarter was the second state released in the historic 50 State Quarters Program. It features the statue “Commonwealth” atop the state capitol dome, an outline of the state, and the motto “Virtue, Liberty, Independence.”

When you examine your coin, check the metal composition. There are two types of 1999-S Pennsylvania quarters: Copper-Nickel Clad and 90% Silver. To tell the difference, look at the edge of the coin. If you see a solid silver stripe with no copper (orange/brown) showing, you likely have the silver version. Using an app like CoinKnow can help you distinguish between these varieties by comparing high-resolution photos.

Significant Value Differences Between Clad and Silver Proofs

The material your coin is made of is the biggest factor in determining its market price. The US Mint produced over 3.7 million Clad proof coins, but only around 800,000 Silver proofs for the Pennsylvania design. Because of the silver content and lower mintage, the silver version is much more desirable.

The 1999 Pennsylvania quarter value depends heavily on whether the coin has maintained its original “Deep Cameo” (DCAM) finish. A Deep Cameo coin features a frosted design that contrasts sharply against a mirror-like background. If yours looks like a mirror, it’s a proof.

Mintage Type	Metal Composition	Current Market Price
1999-S Clad Proof	Copper-Nickel	$3 – $12
1999-S Silver Proof	90% Silver	$25 – $100

Why Grading Matters for 1999-S Quarters

Condition is everything in the world of coin collecting. While a standard silver proof might bring in $30, a perfect specimen graded PR70 by a professional service like PCGS can fetch hundreds. For everyday Americans, it is important to remember that even small scratches, fingerprints, or “haze” on the surface will lower the value from a premium price down to a few dollars.

Collectors look for “eye appeal.” A coin that has shifted to a golden or rainbow tone over time can sometimes sell for more than a blast-white silver coin. Check your Pennsylvania and Delaware state quarter prices frequently, as the market for high-grade 1999 coins fluctuates based on registry set demand.

If you aren’t ready to pay for professional grading, use CoinKnow to get an estimated grade. Most 1999-S quarters found in original mint packaging are likely to grade around PR68 or PR69. The jump from PR69 to PR70 is where the real money is made.

Rare Errors and Varieties to Look For

While the 1999-S Pennsylvania quarter is known for its high quality, errors do happen. Because these are “S” mint proof coins, they undergo a more rigorous inspection process than coins made in Philadelphia or Denver. This makes any error on an “S” mint coin exceptionally rare and valuable.

Common errors to keep an eye out for include double dies, where parts of the text or the design appear doubled. Look closely at the “1787” or the “1999” date. Other mistakes could include “clipped planchets” (where the coin looks like a bite was taken out of it) or “off-center strikes.”

If you suspect you have an error, do not clean the coin! Cleaning a coin with chemicals or a cloth will immediately destroy its collector value. Thousands of dollars have been lost by people trying to make an old coin look “shiny” again. Using a digital tool like CoinKnow allows you to zoom in on tiny details without touching the coin’s delicate surface.

The Historical Significance of the 1999 Second State Quarter

The Pennsylvania quarter holds a special place in the 50 State Quarters Program because it was part of the inaugural year. When these coins were first released in late 1999, the “State Quarter craze” was at its peak. Millions of people began checking their change every day, sparking a new generation of numismatists.

The design itself is rich with symbolism. Pennsylvania is the “Keystone State,” represented by the keystone shape in the design. The “Commonwealth” statue is a bronze statue that stands on the dome of the Pennsylvania State Capitol in Harrisburg.

Because many people saved these coins in the late 90s, the supply for lower grades is high. However, the supply of 1999-S Silver Proofs remains steady, and they are considered a “key date” for anyone trying to build a complete silver state quarter set. Owning a piece of this history, especially in a silver proof format, is a great entry point into serious coin collecting.

Grading Tier	Clad Value (S)	Silver Value (S)
PR65 (Typical)	$3.00	$28.00
PR69 (Near Perfect)	$15.00	$65.00
PR70 (Perfect)	$80.00	$900.00+

Conclusion: Is Your 1999-S Quarter Worth Keeping?

If you have a 1999-S Pennsylvania Quarter, it is definitely worth more than 25 cents. Whether it is worth $5 or $500 depends entirely on its composition and state of preservation. The silver proofs are blue-chip items for state quarter collectors, while the clad proofs are great additions to a starter collection.

Always handle your coins by the edges, store them in PVC-free flips or capsules, and keep an eye out for that “S” mint mark. You might just be holding a valuable piece of American history in the palm of your hand.

Feature	Details
Mint Mark	S (San Francisco)
Weight (Clad)	5.67 grams
Weight (Silver)	6.25 grams
Silver Content	90% Silver, 10% Copper

Frequently Asked Questions

Q: How can I tell if my 1999-S Pennsylvania quarter is silver?

A: The easiest way is to look at the edge (the side with the ridges). If the edge shows a copper layer (a brown/orange stripe), it is the clad version. If the edge is solid silver-white with no copper layer, it is likely the 90% silver version. Additionally, the silver version weighs 6.25 grams, while the clad weighs 5.67 grams.

Q: Why is my 1999-S quarter so shiny compared to other quarters?

A: If it has an “S” mint mark and a mirror-like finish, it is a “Proof” coin. These are made using specially polished dies and blanks. The US Mint strikes them twice to ensure high detail and a beautiful finish, which is why they appear much shinier than the coins you use at the vending machine.

Q: Can I find a 1999-S Pennsylvania quarter in my pocket change?

A: It is rare but possible. Proof coins aren’t meant for circulation, but sometimes people spend them or they are stolen from collections. If you find one in change, its value will be lower because it will likely have scratches (known as “impaired proof” status), but it is still worth more than a regular quarter.

Q: Is the 1999-P or 1999-D Pennsylvania quarter valuable?

A: Most 1999-P (Philadelphia) and 1999-D (Denver) quarters are only worth their face value of 25 cents if they have been circulated. However, if they are in pristine, uncirculated condition (MS65 or higher), they can be worth $1 to $20. Rare errors on these coins can be worth much more.