In this article, you’ll learn about the difference between porosity and permeability, and get your list (and description) of 12 different kinds of porous rocks.
Types of Porous Rocks (With Examples of Porous Rocks)
What makes a rock geologically porous?
Porosity is simply a measure of how much empty space exists in a material. It’s usually expressed as a percentage of the total volume.
For example, if a rock has a porosity of 20%, that means that 20% of its volume is empty space.
To be considered a porous rock, the rock must be able to hold and retain fluids. This means that the pores or voids in the rock must be interconnected, so that fluid can flow freely through them.
There are two main types of porosity: primary porosity and secondary porosity.
Primary porosity is created when a rock forms. It results from the spaces between grains of sediment, or from bubbles of gas that get trapped in lava as it cools.
Secondary porosity is created after a rock has already formed. It can be caused by things like the dissolution of minerals, or the formation of fractures (cracks) in the rock.
Examples of Porous Rocks
There are many different types of porous rocks, including:
-Sandstone: Sandstone is a sedimentary rock composed of sand-sized grains of minerals, rocks, or organic material. It also has a high porosity, which makes it ideal for storing fluids. It is well known for its use in construction and as a building material.
-Limestone: Limestone is a sedimentary rock composed of calcium carbonate. It has a high porosity, which makes it ideal for storing fluids. It is often used in construction and as a building material.
-Dolomite: Dolomite is a sedimentary rock composed of calcium magnesium carbonate. It has a high porosity, and is often used in water treatment and as a construction material.
-Pumice: Pumice is a volcanic rock with a high porosity. It is often used in gardening and horticulture. It is generally one of the easiest rocks to identify because of its unique texture.
-Conglomerate: Conglomerate is a sedimentary rock composed of rounded pebbles or cobbles. It has a high porosity and is often used in construction.
-Scoria: Scoria is a volcanic rock with a high porosity. It is often used in landscaping and gardening.
-Porphyry: Porphyry is an intrusive igneous rock with a porosity that can range from low to high. It is often used in construction.
-Tuff: Tuff is a volcanic rock with a high porosity. It is often used in construction.
-Gneiss: Gneiss is a metamorphic rock with a variable porosity. It is often used in construction.
-Diatomite: Diatomite is a sedimentary rock composed of the fossilized remains of diatoms. It has a high porosity and is often used in filters and absorbents.
-Rock salt: Rock salt is a sedimentary rock composed of sodium chloride. It has a high porosity and is often used in water treatment and de-icing.
-Gypsum: Gypsum is a sedimentary rock composed of calcium sulfate. It has a high porosity and is often used in construction.
You might also be familiar with:
-Shale: Shale is a sedimentary rock composed of fine-grained particles. It has a low porosity and is often used in construction.
-Siltstone: Siltstone is a sedimentary rock composed of silt-sized particles. It has a low porosity and is often used in construction.
-Granite: Granite is an intrusive igneous rock with a low porosity. It is a popular material for countertops and other uses.
-Basalt: Basalt is an extrusive igneous rock with a low porosity. It is a popular material for construction.
Does Porous Mean Permeable?
Porosity and permeability are two related but different concepts.
Porosity is a measure of how much empty space exists in a material, while permeability is a measure of how easily fluids can flow through that material.
A rock can have a high porosity but low permeability, or vice versa.
For example, sandstone has a high porosity but low permeability, while limestone has a high porosity and high permeability.
Porosity and permeability are important properties to consider when trying to store fluids in rocks, or when trying to extract fluids from rocks.
You might also like:
- 7 Examples of Limestone Monuments
- Is Limestone Bad For Dogs?
- Is Limestone Slippery When Wet?
- What Happens When You Mix Limestone With Water?
- Is Limestone a Renewable Resource?
- Is Limestone Permeable?
- Is Limestone Organic?
- Can You Use Limestone To Filter Water?
