This terrazo might just be an ideal base for tile. What is the terrazo on top of? Usually it is put on top of a concrete slab. I have used terrazo on top of plywood but it was epoxy based, with the same rocks, glass or whatever decorative aggregate, and metal strips here and there. If it is portland based (cement) and it is on top of a wood subfloor then I would inspect it closely for any cracks. Hopefully if on wood they used metal mesh and it is as good as most mud beds. If you have ANY cracks then I would apply 1/4" cement board over it first and mesh and mud the joints with thinset. If no cracks then just put the tile directly on it and you will be fine. Before you put either the board or tile I would prep it by sanding down the whole thing with 80 grit or rougher garnet paper using a belt sander or orbital grinder style sander, changing paper frequently when dull. Use thinset mortar for board or tile according to directions, maybe with latex modifier if req.. The sanding will serve to remove any finish that is on the floor and get you right down to the actual terrazo (concrete). The only proviso I have is the metal strips might actually act as cracks so inspect them closely for any separations etc. and don't lay out your tile so that a tile edge lines up directly with a metal strip. If you are worried at all just put the 1/4 board down.