Vesicular Basalt
This is the rock is visible at the top of the cliffs at Kalae on the Island of Hawaii. Basalt with holes or vesicules making up to 50% of the rock is called vesicular basalt. (When the vesicles are over half the volume of a specimen, it is called scoria.) These textures forms when dissolved gases come out of solution and form bubbles as the magma decompresses at the surface. Some gas escapes yet other gas bubbles get trapped in the lava as it quickly hardens. The holes are left by the traped gases.
Vesicular Basalt
This is the rock is visible at the top of the cliffs at Kalae on the Island of Hawaii. Basalt with holes or vesicules making up to 50% of the rock is called vesicular basalt. (When the vesicles are over half the volume of a specimen, it is called scoria.) These textures forms when dissolved gases come out of solution and form bubbles as the magma decompresses at the surface. Some gas escapes yet other gas bubbles get trapped in the lava as it quickly hardens. The holes are left by the traped gases.