About The Mark Index

The Mark Index is a reference for one job: working out who made a piece of pottery, stoneware, costume jewelry or silver, and roughly when, from the mark on it. We built it for people standing in a thrift aisle or an estate sale with a piece turned upside down, and for anyone sorting through things they’ve inherited.

What each entry contains

Every maker entry lists the marks that maker used, written out as transcriptions (the words and line breaks, not a picture), with how each mark was applied, its shape and symbols, where on the piece it appears, and the years it was in use. Then come the dating clues, known look-alikes and reproductions, and the sources the entry was built from.

How we research

• Sources first. Entries are built from museum collection records, collectors’ society references, company histories, historical societies, university and library guides, and established auction houses. Each entry lists at least two.
• Dates as the sources give them. When sources give different dates, we use the range most of them support, label the entry “Sources partly disagree” and explain the disagreement on the page.
• Nothing filled in. If no source says how a mark was applied, or what year it changed, the field stays blank. A blank is more useful to you than a guess.
• Wording is quoted, not reconstructed. Where a source describes a mark instead of quoting it, the description is shown in italics inside the transcription so you can tell the difference.

How we use AI

We use AI tools to help gather and organize sources, draft entries from those sources and check them against each other. Every fact on the site must trace back to a listed source. The illustrations on guides and category pages are generated images. They show general objects, like a crock or a brooch, and never a maker’s mark. We don’t show pictures of marks until we have real photographs we have the right to publish.

What we don’t do

• We don’t give values or prices. They change with the market, condition and demand, and a mark alone can’t tell you what a piece is worth.
• We don’t authenticate. A mark points to a maker and a date range, but marks are also faked and reissued. Where sources warn about reproductions, we say so on the entry.

Corrections

If you have a source showing an entry is wrong, we want to fix it. Corrections that come with a source are checked and added, and the entry’s updated date changes.