The pore spaces (known as vesicles) in pumice are a clue to how it forms. The vesicles are actually gas bubbles that were trapped in the rock during the rapid cooling of a gas-rich frothy magma. The material cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.umice is produced in two forms: rock pumice and pumicite. Pumicite is a name given to very fine grained pumice (less than 4 millimeters in diameter down to submillimeter sizes).
Post and lintel construction is recognized by its simple vertical and horizontal design, in which a pair of vertical supports are set in the ground or a foundation, and a horizontal structure is balanced on top of them.
For the Classic Period of the Mayas, the following major classes of stone sculpture may be distinguished. 1  Stelas. 2  Lintels spanning doorways, and panels and tablets set in the walls and piers of buildings and the sides of platforms. 3  Altars, rounded or rectangular, sometimes resting on three or four boulder-like legs.