I have the spoons from the same brand that makes these chopsticks, and they are nicely solid and have held up well, so I suspect the chopsticks should be similar.

It's true that stone bowls are very expensive online, though, and when you find them in a store, you sometimes need to inspect them because some have little chips or whatever, so I've been suspicious of buying one from Amazon. Ironically, the cheapest ones I've found have precisely been from a small Korean market in a small town, though!