The porosity and permeability of granite are both poor. It is long-lasting, but not as long as quartz. Marble has a larger porosity than granite and is more vulnerable to acidic chemicals such as vinegar. Glass has the highest porosity of all common materials used for sinks and baths. It can be completely dissolved in acid, leaving nothing behind. Porosity is the amount of space between its grains. Quartz is the most dense material on Earth and therefore has no room between its grains. Granite is less dense than quartz and so has some porosity between its grains. Marbles and glass have much more porosity because they're made up of smaller particles with more empty space between them. Permeability is the ability of a material to allow fluids to pass through it. This is important when choosing materials for drains and pipes. The greater the permeability, the faster water will drain from a container filled with it. Permeability depends on many factors including the grain size of the material. Finely grained materials such as quartz have very little permeability while coarsely grained materials such as gravel have high permeability. Granite is an excellent choice for countertops because it's natural, durable, and easy to maintain. It's also low maintenance compared to other types of surfaces such as wood or stone.