educate me on antique rings, please [View all]

I have an old ring that appears to be some sort of a memorial item. Engraved inside with a woman's name, date of her death 1855. No karat mark, although it seems to be gold. No one in the family can finhd out who this person is; not on ancestry or google.

My question is this: were there instances where gold jewelry was not stamped with karat? I tried a magnet on it; it does not react to magnet.