This is an unmarked, but tested, 15 kt gold horse shoe brooch. It has an intricate floral design and the classic, Lucky 7 horse shoe nail pattern.
It measures 1” x 1” and is 1/8” thick. It closes with a metal pin, which extends slightly beyond the brooch to connect with a simple C clasp, as was in common use at the time. The brooch is in very good antique condition, but there are dents near the hinge and at the C clasp that can only be seen from the back.
Please note that this brooch was designed to hang with the bars of the shoe pointing down. The belief at that time was that the Good Luck should wash over the person wearing it. Why store it up? What good is that? However, if you insist in keeping with post 1950 tradition & wearing it up, the simple C clasp will be less secure.