From this page you can find all awesome stuff that you can create with EMERALD BLOCK. EMERALD BLOCK is in misc blocks category. Ever watched the grass grow (IN REAL LIFE)? It is faster than getting this tree ready for harvest. For basic breaking and levelling up. Hitting it will break it but you need to count the hits yourself. Seed mathematics is very complicated, but you should get at least 1 seed back from splicing EMERALD BLOCK. Will you strike it rich? You just have to count the gems yourself. Will you get enough blocks to build something? You just have to find out yourself.