H Krys thank you for writing in with the following hallmark question.
"Does anyone have an idea as to what this hallmark means? Inside of the "C" there is a crown, a 10k mark and an "E" in a diamond."
Krys, they are not British hallmarks. A crown followed by 18 was used on 18 carat UK GOLD ca 1798 - 1974 . A crown followed by 22 was used on 22 carat UK GOLD - ca 1844 - 1974.
I think you might find the maker's mark is the capital letter E in a diamond used by - EHLERS & Co. (Manufacturing Jewelers, New York, NY, USA) - ca 1892 - 1914
