1999 State Quarter Errors: Value Guide & Rare Varieties
Complete 1999 State Quarter error value guide. Experimental Sacagawea planchets worth $3,000–$10,000+, Pennsylvania DDO up to $10,200, Delaware Spitting Horse, missing clad layers. Identify your rare 1999 quarter now.
Most 1999 State Quarters are worth $0.25 in circulation—but the right error can fetch $3,000 to $10,000+.
- ⭐ Experimental Sacagawea Planchet — gold or brassy color, weighs 5.9–6.3g: $3,000–$10,000+
- ⭐ 1999-P Pennsylvania DDO FS-101 — doubled Washington earlobe: $100–$10,200
- ⭐ 1999-P Delaware Spitting Horse FS-901 — raised line from horse's mouth to rim: $10–$200+
- ⭐ Missing Clad Layer — one copper-red side, weighs ~4.7g: $300–$650
⚠️ Millions of gold-plated "collector" quarters weigh the standard 5.67g and are worth exactly $0.25. A digital scale accurate to 0.01g is your single most important tool.
1999 State Quarter Errors Error Checker
Check your coin for valuable errors and varieties
Values shown are typical retail and auction estimates as of 2025-01. Actual market prices vary based on grade, eye appeal, certification, and current demand.
1999 State Quarter error values vary significantly by state design, grade, and error severity. Registry set competition can dramatically inflate prices for top-population specimens.
Professional authentication (PCGS, NGC, or ANACS) is strongly recommended for any coin suspected of being an experimental planchet, doubled die, missing clad layer, or wrong planchet error. Certified coins command a 30–50% premium over raw examples.
Machine Doubling (flat, shelf-like displacement) is NOT a valuable error variety. It is extremely common on high-mintage 1999 quarters.
Gold-plated or platinum-plated 1999 quarters sold in TV collector sets are considered damaged coins and have ZERO numismatic premium. They weigh the standard 5.67g.
Weight verification is the single most important diagnostic for experimental planchets (5.9–6.3g) and missing clad layers (~4.7g). A digital scale accurate to 0.01g is essential.
The five 1999 State Quarters—Delaware, Pennsylvania, New Jersey, Georgia, and Connecticut—launched the most popular U.S. coinage program in decades. What most people don't know: 1999 was also the year the Mint secretly tested experimental alloys for the upcoming Sacagawea dollar, and that metallurgical experiment left behind some of the rarest error coins of the modern era. Most 1999 quarters are worth face value. But a small number are worth thousands. Check standard 1999 quarter baseline values here—then keep reading to find out if yours is one of the rare ones.
1999 State Quarter Specifications and Mintage
1999 State Quarter Specifications and Mintage
| Series | 50 State Quarters — Inaugural Year |
| Five Designs | Delaware (Jan) · Pennsylvania (Mar) · New Jersey (May) · Georgia (Aug) · Connecticut (Oct) |
| Composition | Clad — cupronickel outer layers (75% Cu / 25% Ni) bonded to pure copper core |
| Normal Weight | 5.67 grams (tolerance ±0.227g) — any coin over 5.9g warrants investigation |
| Diameter | 24.26 mm |
| Edge | Reeded (ridged) |
| Mint Marks | P = Philadelphia · D = Denver · S = San Francisco (Proof only). Mint mark is on the obverse (heads side), to the right of Washington's ponytail, just below "IN GOD WE TRUST." |
| Connecticut Mintage | Over 1.3 billion (highest of the five 1999 designs — also yielded the most mechanical errors) |
| Tools Required | Digital scale accurate to 0.01g · 10× loupe magnifier |
1999-S Proof Quarter Values
San Francisco produced 1999 quarters exclusively as Proofs — in two versions. Clad Proofs: $5–$10.Silver Proofs (from Silver Proof Sets): $10–$15. The 1999-S Silver Proof Set has maintained its value better than almost any other modern proof set. If you have a San Francisco (S) quarter that does not have a mirror-like proof finish, have the mint mark professionally verified — the Mint did not produce 1999-S business strikes. See the PCGS CoinFacts page for the 1999-S Pennsylvania Silver DCAM for population and census data.
Errors on proof coins are virtually non-existent. If one were discovered — a double-struck proof, for example — it would represent a five-figure rarity.
→ Full 1999 State Quarter Value Guide: Baseline Prices by Design and Grade
1999 State Quarter Quick Checks: Do You Have Something Valuable?
1999 State Quarter Quick Checks: Do You Have Something Valuable?
Run through these checks before writing off your coin. You need two tools: a digital scale (accurate to 0.01g, available for under $15) and a 10× loupe (a small magnifying glass used by jewelers and coin dealers). Both are essential for this year.
Normal 1999 quarter at 5.67g (left) versus a possible experimental planchet reading over 5.9g (right).
Check 1 — Experimental Sacagawea Planchet (All P & D Designs)
Weigh the coin. Also inspect its overall color and the edge (the thin side of the coin between obverse and reverse).
Gold or brassy color (Types 1 & 2) OR a greenish/gunmetal hue (Types 3 & 4), plus a weight of 5.9–6.3g. The edge may show no copper core (solid alloy) or an unusual core color. Luster is often satin-like rather than bright.
Millions of 1999 quarters were gold-plated by private companies and sold in TV collector sets. Those weigh the standard 5.67g, have a uniform artificial shine, and show plating covering the reeded edge. They are worth $0.25 only.
Check 2 — Pennsylvania DDO FS-101 (1999-P Pennsylvania Only)
Washington's earlobe on the obverse (heads side). Also examine the lettering in "IN GOD WE TRUST" and "LIBERTY" under 10× magnification.
Distinct doubling spread to the southeast on Washington's earlobe — it appears elongated, as though there is a "shadow ear" underneath. Letter serifs (the tiny feet on letters) show separation or notching. DDO stands for Doubled Die Obverse — a die-manufacturing defect that makes every coin from that die identical.
Machine Doubling (MD) creates a flat, shelf-like step that makes design elements look smaller. A true DDO enlarges the device with rounded secondary images and split serifs. MD is caused by die chatter after the strike and has zero collector value.
Check 3 — Delaware Spitting Horse FS-901 (1999-P Delaware Only)
The reverse (tails side) of a 1999 Delaware quarter. Look at the mouth of Caesar Rodney's horse and trace a line downward toward the 3–4 o'clock position on the rim.
A raised, jagged line extending from the horse's mouth down to the rim — caused by a die clash (the two dies colliding without a coin between them). The line is raised above the coin's surface. Many examples also show parallel scraping lines from the feeder finger mechanism.
A scratch is incuse — cut into the metal. The Spitting Horse line is raised above the field. Under a loupe, post-mint damage lines typically show displaced metal at their edges; the genuine die crack has a sharp, uniform ridge.
Check 4 — Missing Clad Layer Error (P & D)
Both sides of the coin. One or both sides will appear copper-red instead of the normal silver color. This happens when the bonded outer layer was missing before striking.
One side brilliant copper-red, other side normal silver. Then weigh: missing one clad layer = approximately 4.7g (about 15–18% lighter than the standard 5.67g). Missing both layers = 3.7–4.0g. Weight is the only reliable authentication method.
Acid-dipped or chemically stripped quarters appear copper-colored but still weigh 5.67g. Environmental damage can also discolor the surface. A coin with copper color AND standard weight is an altered or damaged coin — not a mint error.
Check 5 — Wrong Planchet Error (P & D)
Overall size and edge of the coin. Compare it side by side to a normal quarter. Design elements near the rim may be cut off.
Coin appears undersized with the state name or date partially cut off at the rim. A quarter struck on a nickel planchet (an easy mismatch in 1999) weighs 5.0g (not 5.67g) and measures ~21.2mm (not 24.26mm). The edge shows a solid alloy — no copper core layer visible.
Broadstrikes (struck without the retaining collar) are larger than normal and still weigh 5.67g. Wrong planchet errors are smaller than normal and have a distinctly different weight. Clipped planchets are missing a piece but otherwise use the correct metal stock.
⚠️ Common Traps — Worth Face Value Only
Trap: Gold or Platinum Plating
A shiny gold or silver-toned quarter — often found in a display box from a TV offer or estate sale.
Private companies plated millions of 1999 quarters in gold or platinum and sold them as collectors' items. Numismatists classify these as damaged coins. They have zero numismatic value.
Weigh it. Plated quarters weigh the standard 5.67g. Genuine experimental planchets weigh 5.9–6.3g. If it weighs 5.67g, it is a novelty item worth $0.25. Full trap guide →
Trap: Machine Doubling (MD)
Flat, shelf-like steps next to the date, lettering, or design elements — looks like doubling at first glance.
MD is caused by the die bouncing or sliding after the strike. It is extremely common on the high-mintage 1999 quarters and has zero collector premium.
MD makes design elements look smaller and shows flat shelving. The genuine PA DDO FS-101 enlarges elements with rounded secondary images and split serifs — a completely different look. Full trap guide →
1999 State Quarter Error Values: At-a-Glance Table
1999 State Quarter Error Values: At-a-Glance Table
Baseline values (no errors): Circulated 1999 State Quarters = $0.25 face value. Uncirculated (no wear, full luster) = $0.50–$5.00. High-grade uncirculated (MS66+) = $10–$50+. 1999-S Clad Proof = $5–$10. 1999-S Silver Proof = $10–$15. All values below reflect certified (PCGS/NGC) examples; raw (uncertified) coins typically sell 30–50% lower.
| Error Type | Designation | Mint | Rarity | Value Range | Top Auction Record |
|---|---|---|---|---|---|
| Experimental Planchet | — | P / D | Extreme (<30 known) | $3,000–$10,000+ | $4,888 (PCGS MS66) |
| PA Doubled Die Obverse | FS-101 | P | Scarce | $100–$10,200 | $10,200 (PCGS MS67) |
| Missing Clad Layer | — | P / D | Scarce | $300–$650 | $650 (NGC AU-55) |
| Wrong Planchet (Nickel) | — | P / D | Very Rare | $380–$550 | ~$550 |
| Multi-Strike (3× or 4×) | — | P / D | Very Rare | $575–$780+ | $780 (GA Quad-Strike) |
| DE Spitting Horse | FS-901 | P | Common variety | $10–$200+ | $200 (MS66+) |
| Major Off-Center (50%+) | — | P / D | Rare | $200–$800 | — |
| Broadstrike | — | P / D | Uncommon | $10–$100+ | — |
| Minor Die Cracks | — | All | Common | $1–$5 | — |
| Plated/colorized novelty coins — face value only ($0.25) | |||||
1999 State Quarter Valuable Errors: Detailed Guides
1999 State Quarter Valuable Errors: Detailed Guides
Below is everything you need to identify and value each major 1999 State Quarter error. Each section covers how to find it, how to confirm it, what it's not, and what it's worth.
1999 Experimental Sacagawea Dollar Planchet
Normal 1999 quarter (left) vs. experimental planchet with brassy gold coloration (right), showing satin luster and unusual edge.
Origin & Background
In 1999, the U.S. Mint was finalizing the alloy for the new Sacagawea "golden dollar." The goal was a coin with a golden appearance that would still work in vending machines. Experimental strips of manganese brass were being tested at the same facilities producing State Quarters. Through a failure in material segregation, a tiny number of these experimental planchet blanks were fed into the quarter production presses. Numismatist Mike Byers classified the resulting errors into four types based on color and the presence or absence of a copper core: Type 1 (gold/brassy, copper core visible), Type 2 (gold/brassy, no copper core), Type 3 (greenish/gunmetal, copper core visible), and Type 4 (greenish/gunmetal, no copper core). Fewer than 20–30 examples are confirmed across all five state designs.
How to Identify
- Weight (primary diagnostic): 5.9–6.3g versus the standard 5.67g. A precision digital scale is mandatory — this is the test that separates genuine errors from plated fakes.
- Color: Gold/brassy (Types 1–2) or greenish/gunmetal (Types 3–4). The color is inherent to the alloy, not a coating.
- Edge: Types 2 and 4 show no copper core on the edge (solid alloy). Types 1 and 3 show an unusual or differently colored core.
- Luster: Satin-like rather than the bright metallic luster of a normal clad quarter. The harder manganese brass alloy also tends to produce a slightly soft strike in the design center.
- Professional verification required: PCGS, NGC, or ANACS certification is an absolute prerequisite before buying or selling any example. Mike Byers documented the first confirmed example in detail.
False Positives to Avoid
The gold-plated novelty quarters sold through TV infomercials in the late 1990s are the single biggest source of false reports. They weigh exactly 5.67g, have a uniform artificial shine, and show thin plating across the reeded edge. Additionally, sintered copper dust from annealing furnaces can discolor the coin's surface but does not change the weight. Any copper-colored or golden quarter that weighs 5.67g is not an experimental planchet — end of investigation.
Market Values
- $3,000–$5,000 — Average certified example, typical eye appeal
- $5,000–$10,000+ — High-grade or exceptional color "Sacagawea Gold" Type 1/2 examples
- $0.25 — Gold-plated novelty coin weighing 5.67g (zero premium)
Auction Record
$4,888 for a PCGS MS66 1999-P Delaware on experimental planchet (PCGS Auction Prices, Heritage Auctions). Private treaty transactions for high-grade examples reportedly approaching $10,000.
1999-P Pennsylvania Doubled Die Obverse — FS-101
Normal 1999-P Pennsylvania quarter ear (left) vs. FS-101 DDO showing southeast doubling on the earlobe (right).
Origin & Background
A DDO (Doubled Die Obverse) is not a striking error — it is a die manufacturing defect. When the hub (a positive-image master die) impresses its design into a working die, a slight misalignment can cause a second, slightly offset impression. Every coin struck from that die will have the exact same doubling in the exact same location. The 1999-P Pennsylvania DDO is classified as Class IV (Offset Hubbing) and Class VIII (Tilted Hub) and is listed in the authoritative Cherrypickers' Guide to Rare Die Varieties as FS-101 (also listed by some attributers as WDDO-001). See Wexler's Doubled Die Database for full diagnostics.
How to Identify
- Primary pickup point — Washington's earlobe: Distinct doubling spread to the southeast, making the earlobe look elongated or as if a secondary "shadow ear" sits underneath. Under 10× magnification this is unmistakable on a genuine example.
- Secondary diagnostics — lettering: "IN GOD WE TRUST" and "LIBERTY" show serif separation or notching — the tiny foot of each letter appears doubled or split.
- The device is ENLARGED: True hub doubling increases the apparent size of design elements with rounded, distinct secondary images. This is the key distinction from machine doubling.
False Positives to Avoid
Machine Doubling (MD) is the primary false positive on this coin. MD creates a flat, shelf-like step that makes the device look smaller, with a dull, squashed appearance under magnification. Compare the earlobe side-by-side with a normal 1999-P Pennsylvania quarter — if the earlobe is not clearly larger and more distinct, it is likely MD. Also watch for die deterioration doubling on heavily used dies, which creates a fuzzy, low-relief secondary image rather than a sharp, offset one.
Market Values
- $100–$300 — MS64–MS65 (most accessible grade range)
- $500–$2,000 — MS66 (scarce, registry set competition begins)
- $10,000+ — MS67 top-population examples (registry set premium)
Auction Record
$10,200 for a PCGS MS67 example. This outlier price reflects intense competition for "Top Pop" (highest population grade) registry set coins — the same variety in MS65 trades around $150.
1999-P Delaware Spitting Horse Die Clash — FS-901
1999-P Delaware reverse showing the raised Spitting Horse die clash line from the horse's mouth toward the rim (3–4 o'clock).
Origin & Background
Despite being called a "die crack," the Spitting Horse is technically caused by a die clash — a different mechanism. During a high-speed press run, a planchet failed to feed into the chamber and the obverse and reverse dies slammed together with no metal to cushion the blow. The outline of Washington's portrait (on the obverse die) impacted the reverse die's field, causing a stress fracture in the die steel. This fracture appears as a raised line on every subsequent coin struck from the damaged die. The variety is recognized by PCGS and NGC; attribution on the certified holder significantly increases liquidity.
How to Identify
- Location: A raised, jagged line extending from the mouth of Caesar Rodney's horse downward and to the right, terminating near the 3:00–4:00 position on the rim.
- The line is RAISED: Metal flowed into the fissure in the die, creating a ridge above the coin's surface — this is the key test. Run your fingernail or a toothpick across it under magnification; it catches on the ridge.
- Feeder finger damage: Many Spitting Horse coins also show parallel scraping lines across the design — caused by the mechanical arm that clears struck coins rubbing against the die face. These do not add additional value but confirm the variety's authenticity context.
False Positives to Avoid
A post-mint scratch is incuse — it is cut into the metal and may show raised metal at its edges. The Spitting Horse line is a clean ridge raised above the field. Die polish lines are possible in this area but are extremely fine, uniform, and lack the jagged, irregular character of the die crack. When in doubt, compare under 10× magnification with a certified example image from the PCGS CoinFacts database.
Market Values & Strategy
- $10–$20 — Circulated (VF–AU)
- $20–$40 — Uncirculated (MS60–MS63)
- $40–$90 — Choice Uncirculated (MS64–MS65)
- $100–$150 — Gem Uncirculated (MS66)
- $200+ — Superb Gem (MS67+)
Auction Record
Certified examples consistently realize $100–$200 at MS66 and above. The market is stable and liquid — the variety is a popular entry point for error collectors, maintaining a reliable price floor.
1999 Missing Clad Layer Error
Missing clad layer error: copper-red reverse (left) next to a normal silver reverse (right). Weight verification is required.
Origin & Background
The standard 1999 quarter is a three-layer "sandwich": two outer cupronickel strips (silver-colored) bonded to a copper core. If the bonding process fails — due to gas bubbles at the interface or a defect in the cladding strip — the outer layer may be absent when the blank is punched and struck. The result is a coin with one (or rarely both) sides showing the raw copper interior. The New Jersey design is particularly collected in this form because the complex reverse design looks visually striking in copper.
How to Identify
- Visual: One side is brilliant copper-red; the other is normal nickel-silver. Both sides bear complete designs.
- Weight (definitive test): One missing clad layer → approximately 4.7g (15–18% lighter than 5.67g). Both layers missing → 3.7–4.0g (extremely rare).
- Color premium: Red (RD) copper surfaces are more valuable than brown (BN) or red-brown (RB). A brilliant copper-red surface significantly increases appeal and price.
False Positives to Avoid
Acid-dipped or chemically stripped quarters appear copper-colored but still weigh 5.67g — the chemical process removes only the outer surface, not a structural layer. Environmental damage and toning can also darken the surface. A copper-colored coin that weighs 5.67g is an altered or damaged piece, not a mint error. Weight is the definitive authentication test.
Auction Record
$650 for a 1999-D New Jersey Missing Clad Layer Reverse graded NGC AU-55 at GreatCollections. The coin weighed 4.6g, confirming the missing reverse layer.
1999 Struck on Wrong Planchet
Quarter design struck on a smaller nickel planchet (right) — design elements are truncated at the rim versus a normal quarter (left).
Origin & Background
Wrong planchet errors occur when a blank intended for one denomination is accidentally fed into presses set up for another. In 1999, the proximity of Jefferson Nickel production to State Quarter production at the same facilities created the opportunity for nickel-denomination blanks to enter the quarter press. The quarter dies then struck the smaller nickel planchet, cropping the outer design elements. Georgia and Delaware designs have documented examples on nickel planchets.
How to Identify
- Size and design truncation: The coin is noticeably smaller than a normal quarter. The state name, date, or rim text is partially cut off because the quarter die is larger than the nickel planchet.
- Weight: A Jefferson Nickel planchet weighs 5.0g (compared to 5.67g for a quarter). This is a definitive diagnostic.
- Edge and alloy: The edge of the coin shows solid alloy — no copper core layer visible — confirming the nickel composition (a solid 75/25 cupronickel alloy, not a clad sandwich).
False Positives to Avoid
Broadstrikes are struck on the correct planchet but without the retaining collar — they are larger than normal and weigh 5.67g. Clipped planchets are missing a piece but have the correct alloy and correct (partial) weight. Wrong planchet errors are smaller than normal with a definitively different weight. Always weigh before drawing conclusions.
Auction Record
1999-D Georgia quarter struck on Jefferson Nickel planchet: approximately $380–$550 range at major auction houses. Certified by PCGS or NGC.
1999 Multi-Strike Error (Double, Triple, Quadruple)
1999 quarter with multiple overlapping strike impressions — the shingled design pattern is characteristic of a genuine multi-strike error.
Origin & Background
A multi-strike occurs when the ejection mechanism fails to remove a struck coin from the collar before the next strike cycle. The coin remains in place and is struck again — or multiple more times. Connecticut, with over 1.3 billion coins struck, generated the most mechanical press-related errors by sheer volume. A triple-struck Connecticut quarter and a quadruple-struck Georgia quarter are documented in auction records.
How to Identify
- Overlapping impressions: Two or more complete (or partial) design impressions are visible, shingled or rotated relative to each other.
- Impressions are struck INTO the coin: The overlapping images show full die detail where not covered by subsequent strikes — they are not scratched or rubbed.
- Shape distortion: Severe multi-strikes often distort the coin's shape. The original design may be nearly obliterated on triple or quadruple strikes.
False Positives to Avoid
Machine Doubling creates a single flat shelf-like shadow, not multiple distinct full-design impressions. Die clashes leave ghost impressions of the opposite side's design on one side, not the same design struck multiple times. A genuine multi-strike shows the same die's design repeated at different positions.
Auction Record
$780 for a 1999-P Georgia quadruple-struck quarter. $575+ for a 1999 Connecticut triple-struck quarter.
1999 Major Off-Center Strike (50%+)
Origin & Background
An off-center strike occurs when the feeder mechanism fails to position the planchet perfectly centered over the anvil die. The hammer die strikes only a portion of the planchet, leaving a crescent-shaped unstruck area. Greater off-center percentage generally commands higher premiums. Coins with the date still visible are significantly more valuable than those where the date is lost in the unstruck area.
How to Identify
- Crescent blank area: A smooth, rounded, featureless area covering 50% or more of the coin — this is the portion of the original planchet that was not under the die.
- Sharp design on struck portion: The struck side should show complete, sharp design detail where present.
- Date visibility: Check whether the date (1999) is fully visible. Coins with a readable date are considerably more desirable.
False Positives to Avoid
Post-mint damage from a vise, machinery, or grinding shows tool marks and compression lines on the affected area. A genuine off-center strike has a naturally rounded, smooth edge on the unstruck crescent — no tool marks, no irregular surface.
Market Values
- $200–$400 — 50% off-center, date not visible
- $400–$800 — 50%+ off-center, date fully visible (most desirable)
1999 Broadstrike Error
Broadstrike 1999 quarter (right) showing expanded diameter and missing reeded edge versus a normal quarter (left).
Origin & Background
A broadstrike occurs when the retaining collar — the ring that surrounds the planchet during striking and imparts the reeded edge — fails to deploy or the planchet does not seat within it. Without the collar's constraint, the metal flows outward freely upon impact. The result is a coin that is flatter, wider, and has a completely plain (smooth) edge. Connecticut's enormous mintage produced the highest absolute number of broadstrikes of the 1999 designs.
How to Identify
- Diameter exceeds 24.26mm — the coin is visibly wider than normal.
- Plain (smooth) edge — no reeding whatsoever. This is the simplest visible check.
- Weight ~5.67g — correct planchet, just struck without the collar. The metal was not removed; it spread outward.
- Design may fade toward rim — the spreading metal dilutes the relief near the edge.
False Positives to Avoid
Coins flattened by being run over by a vehicle or squeezed in a vise will show uneven surfaces and compression damage. A genuine broadstrike has uniform, smooth metal flow from the die strike with no tool marks. Broadstrikes are considered "commodity errors" — plentiful in dealer inventories and not investment-grade unless the expansion is dramatic.
1999 State Quarter Common Traps: Save Yourself the Disappointment
1999 State Quarter Common Traps: Save Yourself the Disappointment
The 1999 State Quarter's popularity generated an enormous volume of altered, damaged, and ordinary coins that are routinely mistaken for errors. These three traps account for the vast majority of false reports.
Gold-plated novelty quarter (left, normal 5.67g weight) versus a genuine experimental planchet (right, 5.9–6.3g, satin luster).
⚠️ Trap 1: Gold and Platinum Plated Novelty Coins
A gold or silver-toned 1999 State Quarter — often in a labeled display folder, plastic sleeve, or wooden box from a TV home-shopping offer.
The State Quarter craze spawned a cottage industry of private companies (e.g., "Gold Edition" sets) that micro-plated millions of 1999 quarters in 24-karat gold or platinum and sold them through television and magazine advertisements. The amount of precious metal used is microscopic — a fraction of a cent's worth.
- Plated coins weigh the standard 5.67g — genuine experimental planchets weigh 5.9–6.3g.
- The plating is visible on the reeded edge (ridges are gold-colored, not copper).
- The surface has a uniform, unnatural metallic shine — not the satin luster of genuine manganese brass.
- Presence of a display folder or "collector set" label is a strong indicator of a novelty item.
Value: Face value only ($0.25).
Machine Doubling on 1999 quarter lettering (left, flat shelving) versus true DDO with rounded, enlarged secondary images (right).
⚠️ Trap 2: Machine Doubling (MD)
A flat, shelf-like step alongside the date, lettering, or design elements on one or both sides. Looks like doubling under a loupe.
When a die is slightly loose or worn, it can "chatter" or slide slightly upon retraction after the strike. This smears a thin shelf of metal from the device without creating a true secondary image. It is extremely common on the high-mintage 1999 quarters and occurs to some degree on most coins from every high-volume run.
- MD makes design elements appear smaller — they look compressed, not enlarged.
- The "doubling" is flat and shelf-like with a step-down cut into the surface — not a rounded secondary image.
- On the PA DDO FS-101, Washington's earlobe is clearly larger with a distinct rounded secondary image. MD would make the earlobe smaller with a flat shadow.
- No major recognized DDR (Doubled Die Reverse) exists for the 1999 Connecticut quarter — what appears as doubled branches is universally confirmed as MD by variety experts including CONECA and Wexler.
Value: Face value only ($0.25).
⚠️ Trap 3: Sintered Copper Dust (Surface Discoloration)
A copper-colored or brassy-tinted quarter that looks like it might be a missing clad layer or experimental planchet — but the design seems normal.
Annealing furnaces used to soften blanks may contain residual copper dust from previous batches. Heat can sinter (bond) this dust onto the surface of the cupronickel blank, creating a copper-colored surface layer without any structural defect in the coin itself.
- Weigh the coin — sintered discoloration is a surface-only phenomenon and does NOT change weight. A sintered coin weighs 5.67g.
- A genuine missing clad layer weighs ~4.7g. A genuine experimental planchet weighs 5.9–6.3g.
- The discoloration on a sintered coin is often patchy, uneven, or localized — not the uniform copper surface of a true missing clad layer.
Value: Face value only ($0.25). Weight is always the deciding test.
1999 State Quarter Grading: How Condition Drives Value
1999 State Quarter Grading: How Condition Drives Value
Coin grading uses a 1–70 scale (the Sheldon scale). For 1999 State Quarter errors, grade dramatically affects price — particularly for the Pennsylvania DDO, where the difference between MS65 and MS67 is roughly $150 versus $10,000+.
📊 Key Grade Benchmarks
- Circulated (VF–AU, grades 20–58): Visible wear on the highest points — Washington's hair and cheekbones. For the Spitting Horse, even circulated examples carry a $10–$20 premium.
- Uncirculated (MS60–MS63): No wear, but significant bag marks (contact marks from other coins in the mint bag). Full luster present.
- Choice Uncirculated (MS64–MS65): No wear, few marks, good eye appeal. The most accessible premium grade range for the PA DDO.
- Gem (MS66): Near-flawless surfaces. Certified population begins to thin significantly. Strong premiums begin here for major varieties.
- Superb Gem (MS67+): Essentially perfect. Registry set competition can create dramatic price premiums at this level — a generic quarter worth $5 in MS66 might be worth $200 in MS67.
Because most 1999 error coins circulated before collectors discovered them, high-grade (MS66+) examples of the Pennsylvania DDO and Spitting Horse are genuinely scarce, supporting premium prices at those grades.
1999 State Quarter Authentication: When to Get Your Coin Certified
1999 State Quarter Authentication: When to Get Your Coin Certified
Professional third-party grading (TPG) means submitting your coin to an independent service — PCGS (Professional Coin Grading Service), NGC (Numismatic Guaranty Company), or ANACS — who authenticate, grade, and seal it in a tamper-evident plastic holder called a "slab." Certified coins command a 30–50% premium over raw (unslabbed) examples on the current market.
When Certification Is Worth It
- Experimental planchet suspects: Authentication is mandatory — the market is flooded with gold-plated fakes, and no serious buyer will pay thousands for an uncertified example.
- Pennsylvania DDO FS-101: Certification confirms the attribution and grade. At MS65 and above, the premium over raw coins makes certification economically essential.
- Missing clad layers and wrong planchets: Certification documents the weight and alloy at the time of grading, providing permanent provenance.
- Delaware Spitting Horse: Attribution on the label increases liquidity significantly, especially for MS65+ examples.
When Certification May Not Be Worth It
- Broadstrikes and minor die cracks valued under $25 — certification fees would exceed the coin's premium.
- Circulated Spitting Horse examples (VF–AU, $10–$20 range) — raw is fine for this market.
⚠️ Do Not Clean Your Coin
Cleaning — even gentle wiping — destroys the original surface and reduces certification grade dramatically. TPG services note cleaned coins on the holder as "details" coins, which sell at a steep discount. Place the coin in a flip or 2×2 holder and do not touch the surfaces.
Dealer referral information coming soon. For now, PCGS and NGC both maintain dealer locator tools on their official websites for in-person evaluation of potential errors.
1999 State Quarter Errors: Frequently Asked Questions
1999 State Quarter Errors: Frequently Asked Questions
Is my 1999 State Quarter worth anything?
Most 1999 quarters in circulation are worth face value ($0.25). Uncirculated examples carry a small premium of $0.50–$5.00. The exceptions are specific error coins — the experimental Sacagawea planchet, the Pennsylvania DDO FS-101, the Delaware Spitting Horse, missing clad layers, and wrong planchet errors. Run through the Quick Checks section above with a digital scale and 10× loupe to determine if your coin is one of those exceptions.
What does an experimental Sacagawea planchet look like?
It has a gold or brassy color (or a greenish/gunmetal hue), and crucially, it weighs 5.9–6.3 grams — heavier than the standard 5.67g. The luster is satin-like rather than bright. The edge may show no copper core (solid alloy) or an unusual core color. These coins are extremely rare — fewer than 30 confirmed examples exist across all five 1999 designs. If you think you have one, seek PCGS, NGC, or ANACS certification before doing anything else.
How do I tell machine doubling from a real doubled die?
Machine Doubling (MD) creates a flat, shelf-like step that makes design elements appear smaller. A true Doubled Die Obverse (like the PA DDO FS-101) creates rounded, distinct secondary images that make the device appear larger, with split serifs on lettering. On the PA DDO, Washington's earlobe is clearly enlarged with a shadow image to the southeast. MD has zero numismatic value; it is caused by die chatter and appears on most high-mintage coins to some degree.
Are gold 1999 quarters valuable?
Almost certainly not. Millions of 1999 quarters were micro-plated in gold or platinum by private companies and sold in TV collector sets. These are considered damaged coins by numismatists and have zero numismatic premium — they are worth $0.25. A genuine experimental Sacagawea planchet (which can look golden) is distinguished by its weight: 5.9–6.3g versus the standard 5.67g. Weigh it first.
What is the Spitting Horse and how rare is it?
The Spitting Horse (FS-901) is a die clash variety on the 1999-P Delaware quarter. A raised, jagged line extends from Caesar Rodney's horse's mouth downward toward the 3–4 o'clock rim, created when the obverse and reverse dies collided without a planchet between them. It is not particularly rare — enough examples exist that the market treats it as an accessible variety. Circulated examples sell for $10–$20; certified MS66 examples sell for $100–$150. It is recognized by PCGS and NGC.
Should I clean my error coin before having it graded?
Never clean a coin. Even gentle cleaning destroys the original surface luster and introduces hairlines visible under magnification. PCGS and NGC will note a cleaned coin as a "details" coin on the holder, which sells at a steep discount compared to a problem-free example. Store your coin in a non-PVC flip or 2×2 holder, handle it by the edges only, and submit it as found.
Does the Connecticut quarter have a real doubled die?
No. Despite frequent reports of "doubled branches" on the Connecticut Charter Oak quarter, variety experts including Wexler (CONECA) have confirmed that the vast majority of these are Machine Doubling — flat shelf-like displacement with zero numismatic value. There is no major premium-commanding DDR recognized for the 1999 Connecticut quarter by major attributers. Collectors should not pay premiums for "doubled branches" on this coin.
What tools do I need to check my 1999 quarter for errors?
Two tools cover the vast majority of checks: (1) A digital scale accurate to 0.01g — essential for experimental planchets (5.9–6.3g) and missing clad layers (~4.7g). Available for under $15 online. (2) A 10× loupe magnifier — essential for the Pennsylvania DDO ear and the Delaware Spitting Horse line. A jeweler's loupe works perfectly and costs under $10.
Sources and Methodology
Sources and Methodology
Values reflect retail and auction market data aggregated through early 2025. All prices are for certified (PCGS/NGC/ANACS) examples unless noted. Sources consulted include:
- PCGS Auction Prices — Washington 50 States Quarters (1999–2008)
- PCGS Auction Record: 1999-P Delaware Experimental Planchet MS66
- Mike Byers Numismatics — 1999-P Delaware Experimental Planchet Documentation
- Wexler's Doubled Die Database — 1999-P Pennsylvania DDO
- GreatCollections Auction — 1999-D New Jersey Missing Clad Layer NGC AU-55
- Coin World — Missing Clad Layer Authentication Guide
- Heritage Auctions (ha.com) — historical lot search for 1999 State Quarter errors
- State Quarter mintage data via statequarterguide.com
Disclaimer: Values shown are typical retail and auction estimates as of January 2025. Actual market prices vary based on grade, eye appeal, certification, and current demand. Registry set competition can dramatically inflate prices for top-population specimens. Professional authentication is strongly recommended for any coin suspected of being an experimental planchet, doubled die, missing clad layer, or wrong planchet error.
A note on images: To help illustrate coin diagnostics and rare varieties — especially complex errors that are difficult to describe in text alone — this guide uses AI-generated images. All written values, diagnostics, and variety attributions have been manually reviewed against the cited sources above. While our editorial team works to ensure every image is accurate and helpful, AI-generated illustrations may occasionally misrepresent fine details. If you spot any discrepancy between an image and its written description, please contact us or leave a comment below — we review all feedback and correct errors promptly. Numismatic knowledge is a community effort, and your input helps us build a more accurate resource for everyone.
