This is a delightful small Art Deco frame, in the geometric style. 10 x 13 rabbet size, about an inch and an eighth wide, probably meant for photographic portraits. Two of the samples I've seen have had photo portraits in them. Because I've seen three of these, they must of been somewhat mass produced, but they are very much a hand made object. Looking at the back, instead of the normal eight cuts for the four joints, we now need sixteen cuts for the eight joints, as seen below.
The geometric ornaments appear to be composition. Looking at the top image, full size, the cracks common to aged composition ornaments are visible. A metal leaf finish, with four different colors of paint, and the toning, and wiping to produce the different "textures". I'm very impressed; none of the work involved in this "simple" frame is easy . The design, itself, is just a delight; so evocative of the 1920's. Below are some finished art deco designs, inspired by this frame , and some other items in my family collection. Art Deco incorporated the modernist geometric, but also took art nouveau forward, using the geometric placements, but with the sweep and flow of nouveau.