This mug is NOT safe for liquid. It is mildly crazed, which means that the glaze looks like it's shattered in place. A lot of pottery does this over time. I've never seen it separate from itself, but liquid can get in the cracks and bacteria can harbor there. Some people are ok with that and wash their crazed dishware in the dishwasher to sanitize it, but I'm not willing to suggest that you do that. In any case, you could use this mug for a whole host of other things... maybe a small plant, or a cup holder or holder of other sorts?  
 
This mug is a teal blue and carved with a fish. 
 
This mug is thrown and trimmed on the wheel. I then add a handmade pulled handle, before coating the mug in underglaze and hand carving the design. It then gets bisque fired, and then glaze fired.