These lovely little pestle and mortars are made by Rosie Brand-- a Los Angeles based ceramicist. They're the perfect size for grinding up small quantities or herbs or spices to make individual cups of tea or spice small dishes. They've been fired at really high temperatures so that they can withstand a good grinding. Each one has its own little hanging rope so that it stays together, and can be hung somewhere in plain sight (because why would you want to put something so pretty away in a cupboard?!).
Because these are all made by hand, there are minor variations in each one-- they are all approximately the same size (4" across, 2.5" high) but that varies a tiny bit for each one.