From Dogcraft Wiki
The stone exchange was founded at the start of Sur3 as a way for players to exchange different types of stone. For example, if you dislike diorite but don't want to see it go to waste, and you needed some andesite or granite, you could go to the stone exchange. All players had to do was put their stone into a chest, and take their desired stone out of another chest.
Alongside the stone variants, the exchange also accepted sandstone, grass, dirt, netherrack, nether brick, quartz, soul sand, magma blocks, and glowstone.
The exchange also housed the crypt. At the crypt, players could exchange NBT heads. Zombie, skeleton, creeper, enderman, drowned, blaze, pigman, pig, cow, mooshroom, sheep, and chicken heads were accepted.
The stone exchange was built by Aiyn84 in February of 2019 and received a NTN connection in the middle of that same year.