This set came to Baduk Club from an antique dealer in Hyogo. Agate and Onyx are a popular choice in China, where this set probably came from originally.
There are 181 onyx pieces (black) and 180 agate pieces (white). The agate have some variance in color, which is typical of that mineral. The black are onyx. They were not measured but appear to be size 36-40 (10mm-11mm thick), but will have some variance in size because such stones are generally not cut with exact precision.
The go bowls are striated marble, with marble lids cut to match. They have great patterns that could almost be mistaken for wood grain.
The bowls are polished on the outside but may not be on the interior / underside. In any case, marble has a hardness of 4, while Agate and Onyx are both around 7, so over time the stones will scratch the marble interior (the marble cannot scratch the stones). Still, you may notice some white dust on the stones, that is marble dust, from the marble bowls where the stones have abraded the interior - it would be a good idea to place a handkercheif under the stones so that they remain clean.
This is a Vintage product.
International Seamail shipping from Japan (to almost everywhere) is already included in the purchase price for free via Japan Post Surface, which takes up to 3 months. You may upgrade to Airmail shipping by adding this upgrade to your cart (size Medium) - this also means your items will have more room for padding and spend less time in transit, so they are less likely to be damaged by the shipping. In either case, you will have a tracking number from the shipping service that you can use to sign up for notifications.