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.
Arches and lintels in masonry walls have a different set of loads than in wood frame walls. In a masonry wall, the arch or lintel carries the weight of the masonry immediately above the opening.However, if you draw two lines up toward each other from the top corners of the opening at 45 angles, you'll end up with a triangle.n a masonry wall, the arch or lintel carries the weight of the masonry immediately above the opening. However, if you draw two lines up toward each other from the top corners of the opening at 45 angles, you'll end up with a triangle.