In Europe little we commonly know little about the fine difference between different types of Go stones. As they look basically the same, their thickness varies. Most players and experts agree that about 9mm was perfect, yet it is a matter of taste. As for the material, price, quality, and beauty vary too. Plastic ones are most affordable, yet tend to offer little aesthetical satisfaction. A bit more advanced are those made of “pâte de verre” (French for “glass paste”). This material consists of grinded glass to which a binder has been added. But if you intend to use your stones more often or to have a really nice Go set, you might want to have a look at those made of nacre (mother-of-pearl) which come in white colour. There are actually three levels of quality: Yuki (snow), the most wanted, Tsuki (moon; with more shades of grey), and Jitsuyo (rather brownish). In the same category of quality but of black colour are those made of slate. This little description is to give you a first guideline, but do not hesitate to contact us for any more questions and advice.