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Last updated: August 12, 2026 · By White Metal Resources Editorial
Quick answer: Look at the marks first. Sterling silver is stamped STERLING, STER., 925, or (on British pieces) with a lion passant. Silver plated pieces are stamped EPNS, EP, A1, EPBM, SILVER PLATE, SILVER ON COPPER, or a maker name with no purity number.
Under United States law, only pieces of at least 925 parts per thousand pure silver may be marked STERLING or STER. Only pieces of at least 900 pure may be marked COIN. Plated goods may never carry the words sterling or coin at all.
Short on time? The essentials
- Sterling silver is a solid alloy of 92.5 percent silver and 7.5 percent copper, marked STERLING, STER., 925, or by a national assay mark such as the British lion passant.
- Silver plated pieces are a base metal core (copper, nickel silver, or Britannia metal) with a thin electroplated surface of silver, marked EPNS, EP, A1, EPBM, SILVER PLATE, or with a maker name and no purity number.
- Federal Trade Commission Guides at 16 CFR 23.5 make it deceptive to mark a plated piece STERLING, STER., or COIN in the United States market. The National Stamping Act, 15 U.S.C. 297(a), makes it a stamping violation as well.
- The magnet test rules out iron-core fakes but is not a sterling test on its own. Silver and copper are both non-magnetic, and most plated silverware uses non-magnetic base metals.
- Look for copper bleed at wear points. Silver plated flatware wears through on handle high spots, on fork tine tips, and on spoon bowl ends, showing a warm orange or yellow copper base under the silver.
- Weigh the piece and compare. Sterling flatware is heavier than typical plated flatware of the same form, because silver at 10.49 grams per cubic centimeter is denser than copper, nickel silver, or Britannia metal.
- EPNS means electroplated nickel silver. EPBM means electroplated Britannia metal. A1 is a nineteenth-century electroplate quality grade. SILVER ON COPPER labels a copper-cored plated piece.
- Melt value on plated pieces is nearly zero: the silver coating is measured in microns and rarely justifies refining fees on a household lot. Value on plate is usually decorative or scrap-copper, not silver melt.
- The traditional nitric acid test destroys a small spot and requires safe handling. A coin dealer or refiner with an X-ray fluorescence (XRF) unit reads a piece non-destructively in seconds and is the safest confirmation for anything worth money.
- Silver held for retirement follows a separate fineness rule at .999 or higher. That topic is covered in our silver IRA fineness explainer and is unrelated to sterling and plated household silver.
Anyone who inherits a boxed tea service or a canteen of flatware runs into the same question. The pieces look silver, they feel heavy in the hand, and there are small marks stamped somewhere on the back. But are they solid silver or a base metal object with a thin coating? The answer decides whether the lot is worth real money or is mostly decorative.
The page below turns the question into a repeatable field method. It starts with the marks, which resolve most cases in seconds. It then covers the magnet, weight, sound, and wear tests that fill in when the marks are worn or absent. It ends with the acid and X-ray fluorescence tests that a dealer uses to confirm.
What sterling silver and silver plate actually are
Sterling silver is an alloy composed by weight of 92.5 percent silver and 7.5 percent other metals, usually copper, according to the standard reference on the alloy. The sterling standard has a minimum millesimal fineness of 925 parts per thousand pure silver.
A sterling piece is solid metal all the way through. Cut a fork tine in half and the cross section is the same alloy the surface shows. Wear does not expose a different metal underneath, because there is nothing else there.
Silver plate is different in its construction. A plated piece is a base metal object (usually copper, nickel silver, or Britannia metal) with a thin surface layer of pure silver added by an electrochemical process. The silver layer is measured in microns and is thinner than a sheet of paper.
Two plating families dominate the antique silverware market. The older is Old Sheffield Plate (OSP), developed by Thomas Boulsover in the 1740s, which fuses a sheet of sterling silver to a copper core under heat and pressure. The newer is electroplate, patented by George and Henry Elkington in Birmingham in 1840, which uses electrolysis to deposit pure silver on a base metal core.
United States law: STERLING, COIN, and plated marks
Federal Trade Commission Guides at 16 CFR 23.5 govern how a silver piece may be marked and sold in the United States. The section reads that it is deceptive to use the words solid silver, Sterling Silver, Sterling, or the abbreviation Ster. on any product unless it is at least 925 parts per thousand pure silver.
The same section reads that it is deceptive to use the word coin or the phrase coin silver on any product unless it is at least 900 parts per thousand pure silver. The word silver used unqualified must be preceded by a fineness number in parts per thousand, such as 750 silver, for any product marked and sold in the United States market.
The National Stamping Act at 15 U.S.C. 297(a) is the underlying stamping law and reads that silver plated articles shall not be stamped, branded, engraved, or imprinted with the word sterling or the word coin, either alone or in conjunction with other words or marks. The reader can treat that as a hard line: a piece stamped SILVER PLATE or SILVER ON COPPER cannot also be stamped STERLING under United States law.
The National Stamping Act also sets tolerances. Sterling silver articles or parts that contain no solder have a permissible tolerance of four parts per thousand below the 925 fineness minimum. If the tested part contains solder, the tolerance widens to ten parts per thousand, per the statutory text at 15 U.S.C. 294.
Step one: read the marks first
Marks resolve most sterling versus plated cases in seconds. Turn the piece over, use raking light from a phone flashlight, and read the small stamps punched into the metal. A single legible STERLING or 925 stamp on an American piece is a legal claim of solid silver at .925 fineness.
A single lion passant on a British piece (a walking lion in profile) is the British sterling silver assay mark. It has been in use since a 1544 Tudor statute. Today it is enforced by the four active British assay offices in London, Birmingham, Sheffield, and Edinburgh. Deep dives on world hallmarks live in our companion silver hallmarks guide.
Plated pieces carry a different set of marks entirely. Common electroplate marks are EPNS (electroplated nickel silver), EP (electroplate), EPBM (electroplated Britannia metal), A1 (an old electroplate quality grade), SILVER PLATE, SILVER ON COPPER, and QUADRUPLE PLATE. None of these is a claim of solid silver. All of them mean the surface is silver and the body is a base metal.
Some plated pieces carry only a maker's name (Rogers Bros., Wm. Rogers, Community, Oneida, Reed and Barton for Silverplate) with no purity number and no purity word. Under 16 CFR 23.5 that maker mark, with no fineness disclosure, is a plated piece by default and cannot be marketed as silver without qualification.
Common marks on sterling and on plate, decoded
The table lists the marks a general reader is likely to see on an inherited or estate silver lot in the American market. The left column resolves to solid silver. The middle column resolves to plated silver. The right column notes what each mark means in one line.
| Solid silver marks | Silver plated marks | What the mark tells you |
|---|---|---|
| STERLING or STER. | American sterling silver at .925 fineness minimum, per 16 CFR 23.5 | |
| 925 or 925/1000 | Numeric fineness for sterling silver, .925 parts per thousand pure silver | |
| COIN, PURE COIN, DOLLAR, D | American coin silver at .900 fineness, on pieces made ca. 1800 to 1880 | |
| Lion passant (walking lion) | British sterling silver, statutory since 1544, punched by a British assay office | |
| Britannia figure (seated female) | British Britannia silver at .958 fineness, higher than sterling | |
| 800 / 830 / 835 / 900 / 950 | Numeric fineness on continental European or Mexican solid silver | |
| EPNS | Electroplated nickel silver: thin silver layer on nickel silver base | |
| EP | Electroplate: generic mark for any electroplated silver surface | |
| EPBM | Electroplated Britannia metal: thin silver layer on a tin-antimony-copper base | |
| EPC | Electroplated copper: thin silver layer directly on a copper base | |
| A1 | Nineteenth-century electroplate quality grade (heavier deposit); not a purity mark | |
| SILVER PLATE, SILVERPLATE | Generic mark for an electroplated piece under 16 CFR 23.5 | |
| SILVER ON COPPER | Silver electroplated directly on a copper core | |
| QUADRUPLE PLATE, TRIPLE PLATE | Late 1800s American terms for a heavier or lighter silver deposit | |
| Sheffield or Sheffield Plate | Generic marks used on later plated ware from Sheffield, England | |
| NS or German Silver | Nickel silver, no silver content at all despite the name | |
| Alpaca, Alpacca | Trade name for nickel silver, no silver content |
Sources: Electronic Code of Federal Regulations, 16 CFR 23.5 (rules on STERLING, COIN, plated); Wikipedia Nickel silver (EPNS definition, alpacca and German silver as trade names); Wikipedia Old Sheffield Plate (Boulsover 1740s fusion of copper and sterling); Wikipedia Britannia metal (EPBM abbreviation, base metal composition); Wikipedia Sterling silver (Tiffany adopted sterling 1851, Stamping Act of 1906). Checked August 2026.
The magnet test and its real limits
The magnet test is the first physical test in most silver identification guides. Take a strong rare-earth magnet, hold it near the piece, and see whether it sticks. Silver, copper, and pure nickel silver are non-magnetic. If a piece pulls hard on a magnet, it contains a magnetic core such as iron or nickel-plated steel and is not sterling.
The real limit of the magnet test is that it excludes only one class of fakes. A piece that fails the magnet test (does not stick) is not automatically sterling. Most silver plated flatware and hollowware is built on non-magnetic base metals: pure copper, nickel silver at roughly 60/20/20 copper-nickel-zinc, or Britannia metal at roughly 92 percent tin and 6 percent antimony and 2 percent copper.
The magnet test rules out cheap costume-jewelry silver-tone pieces built on a steel core, which are common in modern imports. It does not rule out a mid-twentieth-century EPNS tea service or a 1900s SILVER ON COPPER cake basket. Both will pass the magnet test easily.
Treat the magnet as a screen for iron-core fakes and nothing more. A piece that clears the magnet still needs the mark check, the weight check, and the wear check before it is priced as sterling.
Weight and density: how much heavier sterling feels
Sterling silver is denser than every common base metal used in silver plating. Silver has a density of about 10.49 grams per cubic centimeter. Sterling silver at .925 fineness sits close to the same value, near 10.36 grams per cubic centimeter, because copper at 8.96 grams per cubic centimeter is not far off.
Nickel silver, the most common electroplate base, has a density of about 8.7 grams per cubic centimeter. Copper, the OSP base, is 8.96 grams per cubic centimeter. Britannia metal (a tin-antimony-copper pewter alloy) is much lighter at about 7.5 grams per cubic centimeter. A piece of the same form and thickness in sterling is roughly 15 to 40 percent heavier than the same piece in any of the plated base metals.
The comparison test works best on matched forms. Take a sterling teaspoon of a given length and a plated teaspoon of the same length and set both on a kitchen scale in grams. The sterling reads noticeably heavier. On flatware in particular, the weight gap is large enough that experienced dealers notice it in the hand before they read the mark.
A caution applies to weighted sterling. Weighted candlesticks, weighted salt and pepper shakers, and some sterling handles on knives are legally sterling on the surface but filled with pitch, plaster, or cement in the interior for stability. The weight test misleads on weighted forms, so read the mark and inspect the interior before relying on weight alone.
The ring test: sound and its limits
The ring test is the traditional coin dealer test for solid silver. Hold the piece by an edge and strike it lightly with a metal object such as a coin. A solid sterling piece produces a clear, sustained bell-like ring that lasts one or two seconds. A plated piece produces a shorter, duller thud, because the base metal core dampens the vibration.
The test works well on flat, thin forms: coins, plates, disks, and simple bowls. It is less reliable on complex shapes with hollow bodies, on soldered joints, and on pieces filled with pitch or cement for weighting. A soldered handle on a sterling teapot will not ring the same way as a hand-forged sterling bowl of the same weight.
Treat the ring test as one input among several. A clear ring is consistent with sterling but is not proof. A dull thud is consistent with plate but can also mean solder-heavy sterling. Confirm with the marks, the weight, and the wear points before concluding.
Wear points: where plated pieces bleed copper
The wear test is the single most reliable field test for silver plate on a household lot. A plated piece has a base metal core, and use over decades wears the silver surface layer through in the spots that see the most contact. When the base metal shows, the piece is plated by definition.
On flatware, look at fork tine tips, spoon bowl ends, and high spots on the handle where a hand grips the piece daily. On tea service hollowware, look at foot rims, at the underside of a handle joint, at the raised edges of a shaped rim, and at the interior of a lid where it seats on the pot. On serving pieces, look at the raised curves of the bowl edge and at the finger grips on the handle.
The color of the exposed base metal tells you which base was used. A warm orange or copper-pink color at wear points is copper or Old Sheffield Plate. A pale yellow, faintly greenish color is nickel silver, the EPNS base. A grey pewter color, sometimes slightly bluish, is Britannia metal, the EPBM base. All three colors identify the piece as plated.
Old Sheffield Plate has a signature reference feature called copper bleed at the rims. The Wikipedia article on Old Sheffield Plate notes that the characteristic identifying feature is the bleeding or show-through of the copper base, especially on points of wear. A piece with copper bleed at the rim of a tea salt or the foot of a candlestick is a Boulsover-lineage OSP piece from the 1740 to 1840 window, and is not solid silver.
A six step sequence for identifying a piece in hand
The six steps below turn the tests above into one repeatable field sequence. Follow the sequence in order on any piece that might be sterling or plated. Most cases resolve at step 2 or step 5.
- Turn the piece over and locate every stamp. Marks sit on the back of a spoon or fork bowl, under the foot of a tea pot or a bowl, and inside the lid rim of a hinged box. Use raking light from a phone flashlight so the shallow stamps show against the polished surface.
- Read the mark first. STERLING, STER., or 925 on an American piece is solid silver by law. A lion passant on a British piece is British sterling. EPNS, EP, A1, EPBM, SILVER PLATE, or SILVER ON COPPER is plated. A maker's name with no purity number is plated by default under 16 CFR 23.5.
- Run the magnet test to rule out iron cores. Hold a rare-earth magnet near the piece. Any pull means an iron or steel core, and the piece is not sterling. No pull is consistent with sterling, with copper, with nickel silver, or with Britannia metal, so this test only excludes one class of fakes.
- Weigh the piece against a matched form. Set the piece on a kitchen scale in grams. Compare to a known sterling piece of the same shape and size. Sterling reads roughly 15 to 40 percent heavier than the same form in plated nickel silver, copper, or Britannia metal.
- Inspect wear points for base metal bleed. Look at fork tines, spoon tips, high spots on handles, foot rims of tea service pieces, and raised edges of shaped rims. Any warm orange (copper), pale yellow-green (nickel silver), or grey (Britannia metal) color under the silver identifies the piece as plated.
- Confirm with a nitric acid spot test or an X-ray fluorescence read. The acid test destroys a small spot but reads at home. XRF at a coin dealer reads the piece non-destructively in seconds and pins the fineness to within a few parts per thousand. Use XRF for anything worth real money.
Any piece that clears step 2 (a legible sterling mark), step 3 (no magnet pull), and step 5 (no base metal bleed at wear points) is sterling with a high degree of confidence. Any piece that fails at step 2 (no sterling mark) and shows base metal bleed at step 5 is plated with a high degree of confidence.
Sterling vs plated: density and silver content at a glance
The chart below places sterling silver and the three common plated base metals on one density scale, alongside the millesimal silver content of each. It makes visible how much denser sterling is than nickel silver or Britannia metal, and how the silver content in a plated piece sits at effectively zero for melt purposes.
Two practical takeaways sit in the chart. First, the weight test is not a rounding error: a sterling teaspoon at the same length as an EPNS teaspoon is real grams heavier, and a scale in grams reads the gap. Second, the silver in a plated piece is a surface layer, so scrapping a plated set for silver melt returns essentially nothing, even on a heavy tea service.
A worked example on a serving spoon
Reading a mark and running the weight and wear tests decides whether a piece is priced by melt or by decorative value. The example below runs the six steps on one large serving spoon and computes the illustrative melt value at a stated silver spot price.
The same six steps run on a British sterling piece marked with a lion passant, on a Continental piece marked 800 or 835, or on an American coin silver piece marked COIN. The melt math changes only in step 4 (the fineness multiplier), which is 0.958 for a British Britannia silver piece, 0.800 for a German 800 piece, or 0.900 for a COIN piece.
The nitric acid test: what it does and its risks
The nitric acid spot test is the traditional destructive silver test. Concentrated nitric acid dropped on solid silver dissolves a small amount of the silver and produces a milky white spot on the metal, from the silver nitrate that forms. Dropped on base metals (copper, nickel silver, or Britannia metal) it produces a bright green, blue, or brown reaction, because the copper or nickel oxidizes.
A silver test kit sold for jewelry work usually contains a solution calibrated for sterling: it produces a distinct red or dark spot on .925 silver, a different color on .800 silver, and yet another on plated or base metal. Test kits ship with a color reference chart printed on the label.
The test is destructive on the surface. It leaves a small etched spot where the acid touched the metal. The test also requires strong protective handling: nitric acid burns skin and clothing, produces toxic brown nitrogen dioxide fumes, and must be neutralized and disposed of properly. Anyone running an acid test should work outdoors or under a fume hood, wear nitrile gloves and eye protection, and keep a baking-soda paste on hand for neutralizing spills.
The acid test is useful on unmarked scrap silver where destroying a small spot does not matter and where the reader has the safety gear. It is not the right first choice on a marked family piece or on any object where surface damage lowers the value.
X-ray fluorescence at a dealer: the non-destructive gold standard
X-ray fluorescence (XRF) is the confirmation test any coin dealer or refiner uses today. An XRF unit fires a low-energy X-ray beam at the surface, reads the fluorescent signal from the metal, and prints the alloy composition in seconds. The reader gets a receipt with the silver fineness to within a few parts per thousand, plus the composition of the base metal if any.
The test is non-destructive. It leaves no mark on the piece and takes about one second per reading. Most coin dealers offer an XRF check on drop-in pieces at no charge as a service to walk-in customers, in the hope of buying a lot at spot minus a spread.
XRF reads the surface, not the full cross section. On a heavily plated piece the surface layer can throw a high silver reading and mask the base metal core. Any dealer running an XRF check on unmarked or suspect silver will also weigh the piece, compare the reading against the theoretical weight of solid silver at that reading, and check the piece by eye at wear points before pricing.
For any single piece worth more than the walk-in cost, XRF at a coin dealer is the safest confirmation. It is faster than an acid test, more accurate than a magnet-and-weight combination, and leaves the piece unchanged.
What plated silver is really worth
The honest number on plated silver is that its melt value is essentially zero. The silver deposit in electroplate is measured in a few microns, or millionths of a meter, added at manufacture to give a durable silver surface. A full tea service in EPNS or EPBM may carry less than a gram of pure silver total across the whole set.
Refiners typically decline plated silver for that reason. The refining fee to recover a few grams of silver from many kilograms of base metal is higher than the recovered silver is worth. A coin dealer will not offer silver melt on plated flatware and will usually decline to weigh a plated lot at all.
Plated silver holds two forms of non-melt value. First, decorative value on identified sets. A complete boxed canteen of English EPNS flatware with a matching serving set from a named maker can sell to a decorator or a table-setting buyer at a modest premium over base metal scrap.
Second, collector premium on high-end Old Sheffield Plate. OSP by identified silversmiths in the 1740 to 1820 window can sell above solid silver melt in strong collector categories. These pieces are priced against completed public auction sales for the specific maker and form.
For a typical household lot of unnamed twentieth-century EPNS or SILVER PLATE flatware, the honest expectation is that the pieces sell at yard-sale or estate-sale prices on decorative merit alone. The full picture on plated silver value lives in our companion article, is silver plate worth anything.
Limits and caveats to keep in mind
Every mark on this page is a stamped claim by the maker or the assay office, not a live assay of the piece in hand. A stamped mark asserts the standard the piece was made to, but an object can be worn, repaired, or altered in ways that change its actual metal content over a long working life. Faked marks also exist in the trade, especially on modern counterfeit pieces.
Every melt figure on the page is a computation from a stated silver spot price, not a live market quote. Silver spot moves continuously during market hours. All dollar figures use example spot prices of 20, 30, or 40 dollars per troy ounce, picked as clean round numbers rather than as predictions.
The weight comparison test assumes the two pieces being weighed are the same form. A large ornate sterling serving spoon can weigh less than a small dense plated ladle if the shapes are different. Match the form before drawing conclusions from the weight alone.
Weighted sterling and cement-filled sterling handles behave differently on the weight test than solid sterling. The mark is still valid on the surface, but the piece is not solid metal all the way through, so the weight is not a pure silver weight. Weighted candlesticks in particular are commonly stamped STERLING on the base but hold a plaster or cement core.
Collector premiums for named makers, forms, and periods are qualitative and vary with the market. This page does not quote dollar values on maker premiums, because those depend on completed public auction sales for the specific maker and form. Anyone with a signed or identified piece should check specialist auction records before pricing.
Silver held for retirement follows a separate fineness rule. The Internal Revenue Code sets the fineness minimum for silver held in a self-directed IRA at .999, well above the .925 sterling standard and far above every plated grade covered on this page. Sterling and plated household silver are fine to own personally but cannot sit inside a self-directed IRA, a topic covered in our silver IRA fineness explainer.
Sterling vs plated: questions answered
How can I tell if my silver is real or plated?
Read the mark first. STERLING, STER., 925, or a lion passant means solid sterling silver at .925 fineness. EPNS, EP, A1, EPBM, SILVER PLATE, or SILVER ON COPPER means silver plated. A maker's name with no purity number is plated by default under 16 CFR 23.5. Then check the wear points for base metal bleed: a warm orange, pale yellow-green, or grey color under the silver is plated.
Does a magnet stick to sterling silver?
No. Sterling silver is non-magnetic, because both silver and copper (the two components of the alloy) are non-magnetic. But most silver plating base metals (copper, nickel silver, Britannia metal) are also non-magnetic. The magnet test rules out iron-core fakes but is not a sterling test on its own.
What does EPNS stand for on silverware?
EPNS stands for electroplated nickel silver. It means the piece is a nickel silver base (a copper-nickel-zinc alloy, usually about 60/20/20 by weight) with a thin electroplated surface layer of pure silver. Nickel silver itself contains no silver despite the name. EPNS pieces are silver only on the surface.
What does A1 mean on silverware?
A1 is a nineteenth-century electroplate quality grade indicating a heavier silver deposit than plain EPNS or EP. It appears on English and American silver plate from about the 1860s onward. A1 is not a purity claim: an A1 piece is still silver plated on a nickel silver or copper base, not solid silver.
What does 925 mean on silver?
A 925 mark means the piece is sterling silver at .925 fineness, or 92.5 percent pure silver by weight. Under 16 CFR 23.5, only pieces at 925 parts per thousand or higher may be marked STERLING or 925 in the United States market. The mark is a legal claim of solid silver.
Is silver plate worth any money?
The melt value on silver plate is essentially zero, because the silver deposit is a thin surface layer measured in microns. Refiners typically decline plated silver. Plated pieces hold decorative or set value in some cases, and high-end Old Sheffield Plate by identified silversmiths from the 1740 to 1820 window can sell above solid silver melt in strong collector categories.
Can silver plate be stamped sterling?
No. The National Stamping Act at 15 U.S.C. 297(a) reads that silver plated articles shall not be stamped, branded, engraved, or imprinted with the word sterling or the word coin, either alone or in conjunction with other words or marks. A piece stamped SILVER PLATE, EPNS, or EPBM legally cannot also be stamped STERLING in the United States market.
Do I need an acid test to identify silver?
Not on marked pieces. A legible STERLING, 925, or lion passant mark combined with a clean wear check is enough for most household lots. The acid test is destructive on the surface and requires safe handling of concentrated nitric acid. On unmarked pieces or on any piece worth real money, an X-ray fluorescence read at a coin dealer is faster, non-destructive, and more accurate.
Sources
- Electronic Code of Federal Regulations, Federal Trade Commission Guides for the Jewelry, Precious Metals, and Pewter Industries, 16 CFR Part 23 (rules on representing silver, sterling silver, coin silver, and silver plate in the United States; deception rules for the words sterling, ster., coin, and silver on marked articles). Checked August 2026.
- Cornell Legal Information Institute, 15 U.S.C. section 297 (National Stamping Act rule that silver plated articles shall not be stamped, branded, engraved, or imprinted with the word sterling or the word coin, either alone or in conjunction with other words or marks). Checked August 2026.
- Cornell Legal Information Institute, 15 U.S.C. section 294 (National Stamping Act tolerances: four parts per thousand below the sterling standard on unsoldered pieces, ten parts per thousand on soldered pieces). Checked August 2026.
- Wikipedia, Sterling silver (alloy composition of 92.5 percent silver and 7.5 percent copper by weight, minimum millesimal fineness of 925, Tiffany adoption of sterling in 1851, Stamping Act of 1906, Baltimore assay office 1814 to 1830). Checked August 2026.
- Wikipedia, Nickel silver (cupronickel alloy with zinc, typical formulation 60 percent copper 20 percent nickel 20 percent zinc, contains no silver despite the name, base metal for EPNS electroplated nickel silver, also called alpacca, argentan, and German silver). Checked August 2026.
- Wikipedia, Britannia metal (pewter alloy of about 92 to 93 percent tin, 5 to 6 percent antimony, and 2 percent copper, used as base metal for silver-plated household goods after electroplating with silver was developed in 1846, abbreviation EPBM on marked pieces). Checked August 2026.
- Wikipedia, Old Sheffield Plate (fusion of copper and sterling silver developed by Thomas Boulsover in the 1740s, characteristic identifying feature is the bleeding or show-through of the copper base at points of wear, subtle bluish lustre in the sterling silver overlay). Checked August 2026.
- Wikipedia, Plating (surface deposition of metal on a substrate, electroplating process invented in the 19th century, Sheffield plate as an earlier fusion process, silver plating on jewelry and hollowware). Checked August 2026.
- Wikipedia, Silver (density of 10.49 grams per cubic centimeter, physical properties including non-magnetic behavior, alloy behavior with copper). Checked August 2026.
- Wikipedia, X-ray fluorescence (non-destructive analytical technique for elemental composition, portable XRF units used in precious metals dealer settings, surface-reading limitation on plated samples). Checked August 2026.
- Cornell Legal Information Institute, 26 U.S.C. section 408 (silver fineness rule for IRA metals at .999 minimum, referenced to the delivery standard of a regulated futures contract). Checked August 2026.
