There isn't a common purity that is 910. Typically you would see 925. The 910 is probably a number that came from the manufacturer or Jeweler.
What caret
There is a purity level of 910 for silver but I don't think that is what its referring to because its rarely used. It might be a marking from the Jeweler you received it from.
Platinum
peanut butter
Early Swarovski Jewelry was marked SAL
Sausalito Craftworks!
375 is the marking for 9 carat gold. Usually vintage European will have this marking.
The 220 hallmark on jewelry means it is a commercial bronze alloy.
HMS is a company that specializes in 18k, 14k, 10k and platinum jewelry
The 833 marking on gold signifies that it is 833 parts pure out of 1000. Translated to karats this would be 20kt, a popular purity used in Portuguese jewelry.
14 Karat Heavy Gold Filled(plated).
HCT is the maker of the jewelry
The question i have is does Edco make any real jewelry?