Citrine-Topaz (?) and Marcasite Sterling Art Deco Ring/Marked Ster[Theda]Ling /Circa 1920's- 30's

I got to rummage through an old wood jewelry box at Salvation today and found this ring among the old religious medals and various other odds and ends. The little bit of info I found was that it was made by the Ideal Mfg Co. in Providence R.I. and they did produce a lot of sterling religious medals. They used "Theda" in the middle of the word "sterling"as their jewelry line name. Supposedly after silent screen actress Theda Bara. The company started doing business in 1921 and continued through the 30's and 40's. I'm not quite sure if the center stone is a real citrine or topaz or just glass. Unfortunately it has a chipped corner. It is studded with marcasites which really do sparkle just not in my picture. The band is a little crooked but all the stones are there. It has a great "art deco" design which I think dates from the 20's 0r 30's. -Mike-