The liner can be made of basalt rocks and river rocks. The liner can be silica which has these two states, first the silica rock produced by foreigners and the other quartzite quarry. The liner can be static or high alamina porcelain and finally the liner can be alumina. Alubite bodies have more than 99% alumina and most importantly the liner can be rubber. The basalt stones are cut into cubes into rectangular cubes. The same is true of silicates.