Guides
How Silver Jewelry Is Made: Hallmarks, Casting and Solid vs Plated
Silver jewelry and hardware craft: how casting, stamping and finishing actually work, what hallmarks state, and how to tell solid silver from plated.
What to take away
- A silver piece is cast, stamped, or raised by hand, and the surface shows which route it took.
- A hallmark records a tested fineness and, in most countries, the maker. It is not a grade.
- Solid sterling, silver plate, and silver filled put different amounts of silver under the surface.
- Plated items wear through to the base metal. Solid items wear down and stay silver.
Where a silver object comes from
Silver reaches the bench as an ingot, a sheet, or a length of wire. Almost every finished piece follows one of three routes, and this guide to lost wax versus sand casting compares two of them.
Casting covers most commercial jewelry. A wax model is invested in plaster, the wax is burned out, and molten silver fills the cavity. Wikipedia's article on lost-wax casting describes the process.
Nearly every cast piece passes through five stages.
- Carve or print the model in wax.
- Attach a sprue and invest the model in plaster.
- Burn the wax out in a kiln.
- Pour molten silver into the cavity.
- Cut the piece free, then file, sand and polish it.
Stamped work starts as sheet and stays uniform. Hand-raised work starts thick and thins toward the rim.
What a hallmark states
A hallmark is a stamped record that an item was tested and met a stated fineness. On sterling the stamp is usually 925, which means 925 parts silver in every 1000. Where no assay office exists, the maker's mark does much of the work, as this guide to how to read a US maker's mark explains.
Wikipedia's article on silver hallmarks compares the marking systems used in Britain, France and the United States. A mark is a claim made at the bench or at assay, and the table below separates the kinds.
| Mark | What it states | What it leaves out |
|---|---|---|
| Fineness mark | Silver content, such as 925 or 958 | Who made the piece |
| Maker's mark | The workshop or smith | Where it was tested |
| Assay office mark | The city or country of assay | The year of testing |
The United States never ran an assay office.
Solid, plated, and filled
Three constructions sit behind the word silver. Solid sterling is the alloy through and through. Silver plate is a thin electroplated layer sitting on copper, brass, or a nickel alloy. Silver filled bonds a thicker sterling layer to a base core.
Federal law ties the word sterling to a fineness of 925, and 15 U.S.C. § 294 sets out that definition. A plated item cannot honestly carry the stamp, and the marking rules appear in this guide to US silver hallmarking laws.
Plating fails first at high points, where a ring rubs a finger or a chain rubs a neck.
Findings and hardware
A clasp decides whether a necklace stays on. Spring rings are light and fine on a light chain. Lobster clasps take more load and suit cold fingers. Anything valuable usually closes with a box clasp and a safety catch.
Check that the jump ring a clasp closes onto is soldered shut. A safety chain is insurance, not decoration.
Example: reading a thrift-store bracelet
A resale bin piece can be read in about a minute. Solid silver and plate differ in four places, and this guide to telling sterling silver from silver plate works through each one.
Check these before you pay:
- Marks
- a fineness stamp and a maker's mark, both deep and crisp.
- Wear
- plate rubs bright at high points, while solid silver dulls evenly.
- Weight
- a plated bangle feels light for its size.
- Joints
- look for a soldered seam on the clasp and the jump rings.
Finishing, firestain and wear
Two defects survive the buffing wheel and come back later. Firestain is a copper oxide that forms in sterling during repeated annealing, and it shows as a purple-gray cloud after polishing. Porosity is gas trapped in a casting, and it opens as tiny pits when the surface is cut back.
A pit that traps polish and turns dark is porosity rather than a scratch. Neither defect is dirt, and both change what a finished object is worth. This guide to firestain, porosity and misleading marks explains how each one reads on a polished piece.
