Regulations, Marks, & Stamps
National Gold and Silver Stamping Act of 1906
In 1906 the US passed a law that all precious metals entering and/or sold in the US must be marked with their precious metal content, i.e. "sterling", "925", "800" etc. Older items may or may not be be marked, and the designations were not standardized.
Gold by karat - 24k, 18k, 14k etc. 'Karat' is the percentage of gold in the item, by weight.
Gold filled (GF): A layer of at least 10k gold is bonded to all surfaces by mechanical means, and the weight of the gold is a minimum of 1/20 of the total weight of the metal.
Gold overlay (GO), and rolled gold plate (RGP) mean the same thing: A layer of mechanically bonded gold that is less than 1/20 of the total weight of the metal but not less than 1/40 of the total weight.
Gold plate: A layer of at least 10k gold that has a minimum thickness of 0.175 micron/7 millionths of an inch (e.g., 14k gold plate).
Vermeil: A layer of gold over sterling silver that has a minimum thickness throughout of 100 millionths of an inch.
Sterling silver: Contains at least 925 parts per thousand by weight of pure silver. Can be marked as sterling silver, solid silver, sterling, ster, or 925.
Country of Origin 1910
Starting in 1910, all items imported or exported in the U.S. were required to have the country of origin stamped on them. Some rosaries that were manufactured around this time have small tags, instead of a stamp.
Nation Name Changes
1916 to 1922: Irish Republic
1922 to 1937: Irish Free State, Eireann
1937 to 1949: Eire or Ireland, although “Ireland” may appear on Irish rosaries of any date.
1949 onward: Republic of Ireland or Eire
Czechoslovakia, Czech Republic
1918 to 1992: Czechoslovakia
Czechoslovakia existed from October 1918 until the end of 1992. Prior to 1918 the bead making region of Czechoslovakia was called Bohemia and was part of the Austrian empire. Bead making in Czechoslovakia was nationalized in 1948, and went into hiatus until about 1958.
1993: Czech Republic
After Czechoslovakia was dissolved Bohemia became part of the Czech Republic.
1963 Zip Codes
5-digit zip codes were introduced in the U.S. in 1963. 9-digit codes were introduced in 1983. Rosaries won't have zip codes (of course), but look at the address on any accompanying pamphlet or packaging.