Markings to signify gold content were not required in the U. S. until the early 1900's. Anything older than that will not likely have any markings. The only way to know for sure is to take it to an expert, like a jeweler, who can do an acid test

• How can you tell if antique jewelry is real gold?
• Gold jewelry recovered 13124711729; jewelry recovered; recovery of gold jewelry; platinum recovery; bullion
• What's the Definition of Antique Jewelry
• How to Choose: Yellow Gold vs White Gold Jewelry
• Where can I buy pure real gold? (not gold shares) What country is gold cheapest in?
• What does 12 K mean on gold jewelry?
• Why is gold used for jewelry?
• How much gold in a 18k 10k jewelry?
• What is rolled gold jewelry?
• How much is a gram of gold in jewelry?