Hallmarks with letter “O”

Hallmarks with letter “O”: 9 records in the reference, dated between 1778 and 1940. By type: masters — 8. Shield shapes here: rectangle — 6, elongated rectangle — 2. The records cover 4 towns and villages. Most frequent: Петтелиус Отто Рейнхольд — 3. 6 different makers and works are named. Every entry carries an image of the mark, its letters, the years it was in use and the shape of the shield. The letters and numerals struck on the mark itself — the maker’s initials, an abbreviated town or works name, an artel number, a year digit. Attribution almost always starts here: first find a mark with the same characters, then check the shield shape and the dates.