In the museum there are 10000 exhibits. But the exchange found has about 30 tons of minerals. And there is no problem to increase that quantity. The museum is based in Sludyanka. It is small city surrounded with mountains. And there are a lot of minerals around. You just have to know where to find them. It’s like a good fisherman knows where fish are hiding; geologist knows where the minerals are. Some times you are going to find one kind of minerals but coming back home with another unique sample.
But if you are not lucky or disappointed with what you have found. The exchange found can help improve it. There are a lot of possibilities of buying minerals by symbolic sum of money for supporting museum. Or you can trade it on other samples.