Identifying a Vintage Ring: O.B. 10K Stone & Design

Question
I have a ring a friend gave me thinking it was junk but I find it fascinating, hopefully you can help.  It has a very large light bluish clear stone in a square cut, VERY worn, the stone is 3/4 by 1/2 inch's. The stone is held is inlaid into the metal on all four sides, like the metal wraps around the edge of the rock on all sides i guess.there is a design embossed on the sides. And the markings inside are... O.B. 10K T  the t is over sized and fat and the stem is almost like a triangle, and the crossed portion is a fat rectangle with no upper inclosure. can you help? please respond to redheadwflair@yahoo.com

Answer
Hello Nikki and thank you for your inquiry. The OB could stand for Ostby and Barton a jewelry firm active in the 1920-40's located in Providence, RI. They were makers of low karat gold jewelry. The "T" could be a design or production company mark. Hope this helps !